diff --git a/backend/.env.example b/backend/.env.example
index 2916e696d1..3da6b66940 100644
--- a/backend/.env.example
+++ b/backend/.env.example
@@ -10,6 +10,13 @@ DJANGO_DB_NAME=None
 DJANGO_DB_PASSWORD=None
 DJANGO_DB_PORT=None
 DJANGO_DB_USER=None
+DJANGO_GOOGLE_AUTH_AUTH_URI=https://accounts.google.com/o/oauth2/auth
+DJANGO_GOOGLE_AUTH_CLIENT_ID=None
+DJANGO_GOOGLE_AUTH_CLIENT_SECRET=None
+DJANGO_GOOGLE_AUTH_REDIRECT_URI=http://localhost:8000/auth/google/callback/
+DJANGO_GOOGLE_AUTH_SCOPES=https://www.googleapis.com/auth/calendar.readonly
+DJANGO_GOOGLE_AUTH_TOKEN_URI=https://oauth2.googleapis.com/token
+DJANGO_IS_GOOGLE_AUTH_ENABLED=False
 DJANGO_OPEN_AI_SECRET_KEY=None
 DJANGO_PUBLIC_IP_ADDRESS="127.0.0.1"
 DJANGO_REDIS_HOST=None
diff --git a/backend/apps/common/clients.py b/backend/apps/common/clients.py
new file mode 100644
index 0000000000..68f1e1fd07
--- /dev/null
+++ b/backend/apps/common/clients.py
@@ -0,0 +1,20 @@
+"""Common API Clients."""
+
+from django.conf import settings
+from google_auth_oauthlib.flow import Flow
+
+
+def get_google_auth_client():
+    """Get a Google OAuth client."""
+    return Flow.from_client_config(
+        client_config={
+            "web": {
+                "client_id": settings.GOOGLE_AUTH_CLIENT_ID,
+                "client_secret": settings.GOOGLE_AUTH_CLIENT_SECRET,
+                "redirect_uris": [settings.GOOGLE_AUTH_REDIRECT_URI],
+                "auth_uri": settings.GOOGLE_AUTH_AUTH_URI,
+                "token_uri": settings.GOOGLE_AUTH_TOKEN_URI,
+            }
+        },
+        scopes=settings.GOOGLE_AUTH_SCOPES,
+    )
diff --git a/backend/apps/nest/models/__init__.py b/backend/apps/nest/models/__init__.py
index 597b834442..5dd1ca2380 100644
--- a/backend/apps/nest/models/__init__.py
+++ b/backend/apps/nest/models/__init__.py
@@ -1,3 +1,4 @@
 from .api_key import ApiKey
 from .badge import Badge
+from .member_google_credentials import MemberGoogleCredentials
 from .user import User
diff --git a/backend/apps/nest/models/member_google_credentials.py b/backend/apps/nest/models/member_google_credentials.py
new file mode 100644
index 0000000000..35b5fc7622
--- /dev/null
+++ b/backend/apps/nest/models/member_google_credentials.py
@@ -0,0 +1,131 @@
+"""Slack Google OAuth Authentication Model."""
+
+from django.conf import settings
+from django.core.exceptions import ValidationError
+from django.db import models
+from django.utils import timezone
+from google.auth.transport.requests import Request
+from google.oauth2.credentials import Credentials
+
+from apps.common.clients import get_google_auth_client
+from apps.slack.models.member import Member
+
+AUTH_ERROR_MESSAGE = (
+    "Google OAuth client ID, secret, and redirect URI must be set in environment variables."
+)
+
+
+class MemberGoogleCredentials(models.Model):
+    """Model to store Google OAuth tokens for Slack integration."""
+
+    class Meta:
+        db_table = "nest_member_google_credentials"
+        verbose_name_plural = "Member's Google Credentials"
+
+    member = models.OneToOneField(
+        "slack.Member",
+        on_delete=models.CASCADE,
+        related_name="member_google_credentials",
+        verbose_name="Slack Member",
+    )
+    access_token = models.BinaryField(verbose_name="Access Token", null=True)
+    refresh_token = models.BinaryField(verbose_name="Refresh Token", null=True)
+    expires_at = models.DateTimeField(
+        verbose_name="Token Expiry",
+        null=True,
+    )
+
+    @staticmethod
+    def authenticate(member):
+        """Authenticate a member.
+
+        Returns:
+            - MemberGoogleCredentials instance if a valid/refreshable token exists, or
+            - (authorization_url, state) tuple to complete the OAuth flow.
+
+        """
+        if not settings.IS_GOOGLE_AUTH_ENABLED:
+            raise ValueError(AUTH_ERROR_MESSAGE)
+        auth = MemberGoogleCredentials.objects.get_or_create(member=member)[0]
+        if auth.access_token and not auth.is_token_expired:
+            return auth
+        if auth.access_token:
+            # If the access token is present but expired, refresh it
+            MemberGoogleCredentials.refresh_access_token(auth)
+            return auth
+        # If no access token is present, redirect to Google OAuth
+        flow = MemberGoogleCredentials.get_flow()
+        flow.redirect_uri = settings.GOOGLE_AUTH_REDIRECT_URI
+        state = member.slack_user_id
+        return flow.authorization_url(
+            access_type="offline",
+            prompt="consent",
+            state=state,
+        )
+
+    @staticmethod
+    def authenticate_callback(auth_response, member_id):
+        """Authenticate a member and return a MemberGoogleCredentials instance."""
+        if not settings.IS_GOOGLE_AUTH_ENABLED:
+            raise ValueError(AUTH_ERROR_MESSAGE)
+
+        member = None
+        try:
+            member = Member.objects.get(slack_user_id=member_id)
+        except Member.DoesNotExist as e:
+            error_message = f"Member with Slack ID {member_id} does not exist."
+            raise ValidationError(error_message) from e
+
+        auth = MemberGoogleCredentials.objects.get_or_create(member=member)[0]
+        # This is the first time authentication, so we need to fetch a new token
+        flow = MemberGoogleCredentials.get_flow()
+        flow.redirect_uri = settings.GOOGLE_AUTH_REDIRECT_URI
+        flow.fetch_token(authorization_response=auth_response)
+        auth.access_token = flow.credentials.token
+        auth.refresh_token = flow.credentials.refresh_token
+        expires_at = flow.credentials.expiry
+        if expires_at and timezone.is_naive(expires_at):
+            expires_at = timezone.make_aware(expires_at)
+        auth.expires_at = expires_at
+        auth.save()
+        return auth
+
+    @staticmethod
+    def get_flow():
+        """Create a Google OAuth flow instance."""
+        if not settings.IS_GOOGLE_AUTH_ENABLED:
+            raise ValueError(AUTH_ERROR_MESSAGE)
+        return get_google_auth_client()
+
+    @property
+    def is_token_expired(self):
+        """Check if the access token is expired."""
+        return self.expires_at is None or self.expires_at <= timezone.now() + timezone.timedelta(
+            seconds=60
+        )
+
+    @staticmethod
+    def refresh_access_token(auth):
+        """Refresh the access token using the refresh token."""
+        if not settings.IS_GOOGLE_AUTH_ENABLED:
+            raise ValueError(AUTH_ERROR_MESSAGE)
+        refresh_error = "Google OAuth refresh token is not set or expired."
+        if not auth.refresh_token:
+            raise ValidationError(refresh_error)
+        credentials = Credentials(
+            token=auth.access_token,
+            refresh_token=auth.refresh_token,
+            token_uri=settings.GOOGLE_AUTH_TOKEN_URI,
+            client_id=settings.GOOGLE_AUTH_CLIENT_ID,
+            client_secret=settings.GOOGLE_AUTH_CLIENT_SECRET,
+        )
+        credentials.refresh(Request())
+
+        auth.access_token = credentials.token
+        auth.refresh_token = credentials.refresh_token
+        auth.expires_at = credentials.expiry
+        auth.save()
+
+    def __str__(self):
+        """Return a string representation of the MemberGoogleCredentials instance."""
+        return f"MemberGoogleCredentials(member={self.member})"
diff --git a/backend/poetry.lock b/backend/poetry.lock
index 6ace034c39..5f85582386 100644
--- a/backend/poetry.lock
+++ b/backend/poetry.lock
@@ -288,6 +288,18 @@ urllib3 = {version = ">=1.25.4,<2.2.0 || >2.2.0,<3", markers = "python_version >
 [package.extras]
 crt = ["awscrt (==0.27.6)"]
 
+[[package]]
+name = "cachetools"
+version = "5.5.2"
+description = "Extensible memoizing collections and decorators"
+optional = false
+python-versions = ">=3.7"
+groups = ["main"]
+files = [
+    {file = "cachetools-5.5.2-py3-none-any.whl", hash = "sha256:d26a22bcc62eb95c3beabd9f1ee5e820d3d2704fe2967cbe350e20c8ffcd3f0a"},
+    {file = "cachetools-5.5.2.tar.gz", hash = "sha256:1a661caa9175d26759571b2e19580f9d6393969e5dfca11fdb1f947a23e640d4"},
+]
+
 [[package]]
 name = "certifi"
 version = "2025.8.3"
@@ -1101,6 +1113,130 @@ dev-test = ["coverage", "pytest (>=3.10)", "pytest-asyncio (>=0.17)", "sphinx (<
 requests = ["requests (>=2.16.2)", "urllib3 (>=1.24.2)"]
 timezone = ["pytz"]
 
+[[package]]
+name = "google-api-core"
+version = "2.25.1"
+description = "Google API client core library"
+optional = false
+python-versions = ">=3.7"
+groups = ["main"]
+files = [
+    {file = "google_api_core-2.25.1-py3-none-any.whl", hash = "sha256:8a2a56c1fef82987a524371f99f3bd0143702fecc670c72e600c1cda6bf8dbb7"},
+    {file = "google_api_core-2.25.1.tar.gz", hash = "sha256:d2aaa0b13c78c61cb3f4282c464c046e45fbd75755683c9c525e6e8f7ed0a5e8"},
+]
+
+[package.dependencies]
+google-auth = ">=2.14.1,<3.0.0"
+googleapis-common-protos = ">=1.56.2,<2.0.0"
+proto-plus = {version = ">=1.25.0,<2.0.0", markers = "python_version >= \"3.13\""}
+protobuf = ">=3.19.5,<3.20.0 || >3.20.0,<3.20.1 || >3.20.1,<4.21.0 || >4.21.0,<4.21.1 || >4.21.1,<4.21.2 || >4.21.2,<4.21.3 || >4.21.3,<4.21.4 || >4.21.4,<4.21.5 || >4.21.5,<7.0.0"
+requests = ">=2.18.0,<3.0.0"
+
+[package.extras]
+async-rest = ["google-auth[aiohttp] (>=2.35.0,<3.0.0)"]
+grpc = ["grpcio (>=1.33.2,<2.0.0)", "grpcio (>=1.49.1,<2.0.0) ; python_version >= \"3.11\"", "grpcio-status (>=1.33.2,<2.0.0)", "grpcio-status (>=1.49.1,<2.0.0) ; python_version >= \"3.11\""]
+grpcgcp = ["grpcio-gcp (>=0.2.2,<1.0.0)"]
+grpcio-gcp = ["grpcio-gcp (>=0.2.2,<1.0.0)"]
+
+[[package]]
+name = "google-api-python-client"
+version = "2.178.0"
+description = "Google API Client Library for Python"
+optional = false
+python-versions = ">=3.7"
+groups = ["main"]
+files = [
+    {file = "google_api_python_client-2.178.0-py3-none-any.whl", hash = "sha256:f420adcd050150ff1baefa817e96e1ffa16872744f53471cd34096612e580c34"},
+    {file = "google_api_python_client-2.178.0.tar.gz", hash = "sha256:99cba921eb471bb5973b780c653ac54d96eef8a42f1b7375b7ab98f257a4414c"},
+]
+
+[package.dependencies]
+google-api-core = ">=1.31.5,<2.0.dev0 || >2.3.0,<3.0.0"
+google-auth = ">=1.32.0,<2.24.0 || >2.24.0,<2.25.0 || >2.25.0,<3.0.0"
+google-auth-httplib2 = ">=0.2.0,<1.0.0"
+httplib2 = ">=0.19.0,<1.0.0"
+uritemplate = ">=3.0.1,<5"
+
+[[package]]
+name = "google-auth"
+version = "2.40.3"
+description = "Google Authentication Library"
+optional = false
+python-versions = ">=3.7"
+groups = ["main"]
+files = [
+    {file = "google_auth-2.40.3-py2.py3-none-any.whl", hash = "sha256:1370d4593e86213563547f97a92752fc658456fe4514c809544f330fed45a7ca"},
+    {file = "google_auth-2.40.3.tar.gz", hash = "sha256:500c3a29adedeb36ea9cf24b8d10858e152f2412e3ca37829b3fa18e33d63b77"},
+]
+
+[package.dependencies]
+cachetools = ">=2.0.0,<6.0"
+pyasn1-modules = ">=0.2.1"
+rsa = ">=3.1.4,<5"
+
+[package.extras]
+aiohttp = ["aiohttp (>=3.6.2,<4.0.0)", "requests (>=2.20.0,<3.0.0)"]
+enterprise-cert = ["cryptography", "pyopenssl"]
+pyjwt = ["cryptography (<39.0.0) ; python_version < \"3.8\"", "cryptography (>=38.0.3)", "pyjwt (>=2.0)"]
+pyopenssl = ["cryptography (<39.0.0) ; python_version < \"3.8\"", "cryptography (>=38.0.3)", "pyopenssl (>=20.0.0)"]
+reauth = ["pyu2f (>=0.1.5)"]
+requests = ["requests (>=2.20.0,<3.0.0)"]
+testing = ["aiohttp (<3.10.0)", "aiohttp (>=3.6.2,<4.0.0)", "aioresponses", "cryptography (<39.0.0) ; python_version < \"3.8\"", "cryptography (>=38.0.3)", "flask", "freezegun", "grpcio", "mock", "oauth2client", "packaging", "pyjwt (>=2.0)", "pyopenssl (<24.3.0)", "pyopenssl (>=20.0.0)", "pytest", "pytest-asyncio", "pytest-cov", "pytest-localserver", "pyu2f (>=0.1.5)", "requests (>=2.20.0,<3.0.0)", "responses", "urllib3"]
+urllib3 = ["packaging", "urllib3"]
+
+[[package]]
+name = "google-auth-httplib2"
+version = "0.2.0"
+description = "Google Authentication Library: httplib2 transport"
+optional = false
+python-versions = "*"
+groups = ["main"]
+files = [
+    {file = "google-auth-httplib2-0.2.0.tar.gz", hash = "sha256:38aa7badf48f974f1eb9861794e9c0cb2a0511a4ec0679b1f886d108f5640e05"},
+    {file = "google_auth_httplib2-0.2.0-py2.py3-none-any.whl", hash = "sha256:b65a0a2123300dd71281a7bf6e64d65a0759287df52729bdd1ae2e47dc311a3d"},
+]
+
+[package.dependencies]
+google-auth = "*"
+httplib2 = ">=0.19.0"
+
+[[package]]
+name = "google-auth-oauthlib"
+version = "1.2.2"
+description = "Google Authentication Library"
+optional = false
+python-versions = ">=3.6"
+groups = ["main"]
+files = [
+    {file = "google_auth_oauthlib-1.2.2-py3-none-any.whl", hash = "sha256:fd619506f4b3908b5df17b65f39ca8d66ea56986e5472eb5978fd8f3786f00a2"},
+    {file = "google_auth_oauthlib-1.2.2.tar.gz", hash = "sha256:11046fb8d3348b296302dd939ace8af0a724042e8029c1b872d87fabc9f41684"},
+]
+
+[package.dependencies]
+google-auth = ">=2.15.0"
+requests-oauthlib = ">=0.7.0"
+
+[package.extras]
+tool = ["click (>=6.0.0)"]
+
+[[package]]
+name = "googleapis-common-protos"
+version = "1.70.0"
+description = "Common protobufs used in Google APIs"
+optional = false
+python-versions = ">=3.7"
+groups = ["main"]
+files = [
+    {file = "googleapis_common_protos-1.70.0-py3-none-any.whl", hash = "sha256:b8bfcca8c25a2bb253e0e0b0adaf8c00773e5e6af6fd92397576680b807e0fd8"},
+    {file = "googleapis_common_protos-1.70.0.tar.gz", hash = "sha256:0e1b44e0ea153e6594f9f394fef15193a68aaaea2d843f83e2742717ca753257"},
+]
+
+[package.dependencies]
+protobuf = ">=3.20.2,<4.21.1 || >4.21.1,<4.21.2 || >4.21.2,<4.21.3 || >4.21.3,<4.21.4 || >4.21.4,<4.21.5 || >4.21.5,<7.0.0"
+
+[package.extras]
+grpc = ["grpcio (>=1.44.0,<2.0.0)"]
+
 [[package]]
 name = "graphql-core"
 version = "3.2.6"
@@ -1238,6 +1374,21 @@ http2 = ["h2 (>=3,<5)"]
 socks = ["socksio (==1.*)"]
 trio = ["trio (>=0.22.0,<1.0)"]
 
+[[package]]
+name = "httplib2"
+version = "0.22.0"
+description = "A comprehensive HTTP client library."
+optional = false
+python-versions = ">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*"
+groups = ["main"]
+files = [
+    {file = "httplib2-0.22.0-py3-none-any.whl", hash = "sha256:14ae0a53c1ba8f3d37e9e27cf37eabb0fb9980f435ba405d546948b009dd64dc"},
+    {file = "httplib2-0.22.0.tar.gz", hash = "sha256:d7a10bc5ef5ab08322488bde8c726eeee5c8618723fdb399597ec58f3d82df81"},
+]
+
+[package.dependencies]
+pyparsing = {version = ">=2.4.2,<3.0.0 || >3.0.0,<3.0.1 || >3.0.1,<3.0.2 || >3.0.2,<3.0.3 || >3.0.3,<4", markers = "python_version > \"3.0\""}
+
 [[package]]
 name = "httpx"
 version = "0.28.1"
@@ -2134,6 +2285,23 @@ files = [
     {file = "numpy-2.3.2.tar.gz", hash = "sha256:e0486a11ec30cdecb53f184d496d1c6a20786c81e55e41640270130056f8ee48"},
 ]
 
+[[package]]
+name = "oauthlib"
+version = "3.3.1"
+description = "A generic, spec-compliant, thorough implementation of the OAuth request-signing logic"
+optional = false
+python-versions = ">=3.8"
+groups = ["main"]
+files = [
+    {file = "oauthlib-3.3.1-py3-none-any.whl", hash = "sha256:88119c938d2b8fb88561af5f6ee0eec8cc8d552b7bb1f712743136eb7523b7a1"},
+    {file = "oauthlib-3.3.1.tar.gz", hash = "sha256:0f0f8aa759826a193cf66c12ea1af1637f87b9b4622d46e866952bb022e538c9"},
+]
+
+[package.extras]
+rsa = ["cryptography (>=3.0.0)"]
+signals = ["blinker (>=1.4.0)"]
+signedtoken = ["cryptography (>=3.0.0)", "pyjwt (>=2.0.0,<3)"]
+
 [[package]]
 name = "openai"
 version = "1.100.2"
@@ -2597,6 +2765,43 @@ files = [
     {file = "propcache-0.3.2.tar.gz", hash = "sha256:20d7d62e4e7ef05f221e0db2856b979540686342e7dd9973b815599c7057e168"},
 ]
 
+[[package]]
+name = "proto-plus"
+version = "1.26.1"
+description = "Beautiful, Pythonic protocol buffers"
+optional = false
+python-versions = ">=3.7"
+groups = ["main"]
+files = [
+    {file = "proto_plus-1.26.1-py3-none-any.whl", hash = "sha256:13285478c2dcf2abb829db158e1047e2f1e8d63a077d94263c2b88b043c75a66"},
+    {file = "proto_plus-1.26.1.tar.gz", hash = "sha256:21a515a4c4c0088a773899e23c7bbade3d18f9c66c73edd4c7ee3816bc96a012"},
+]
+
+[package.dependencies]
+protobuf = ">=3.19.0,<7.0.0"
+
+[package.extras]
+testing = ["google-api-core (>=1.31.5)"]
+
+[[package]]
+name = "protobuf"
+version = "6.31.1"
+description = ""
+optional = false
+python-versions = ">=3.9"
+groups = ["main"]
+files = [
+    {file = "protobuf-6.31.1-cp310-abi3-win32.whl", hash = "sha256:7fa17d5a29c2e04b7d90e5e32388b8bfd0e7107cd8e616feef7ed3fa6bdab5c9"},
+    {file = "protobuf-6.31.1-cp310-abi3-win_amd64.whl", hash = "sha256:426f59d2964864a1a366254fa703b8632dcec0790d8862d30034d8245e1cd447"},
+    {file = "protobuf-6.31.1-cp39-abi3-macosx_10_9_universal2.whl", hash = "sha256:6f1227473dc43d44ed644425268eb7c2e488ae245d51c6866d19fe158e207402"},
+    {file = "protobuf-6.31.1-cp39-abi3-manylinux2014_aarch64.whl", hash = "sha256:a40fc12b84c154884d7d4c4ebd675d5b3b5283e155f324049ae396b95ddebc39"},
+    {file = "protobuf-6.31.1-cp39-abi3-manylinux2014_x86_64.whl", hash = "sha256:4ee898bf66f7a8b0bd21bce523814e6fbd8c6add948045ce958b73af7e8878c6"},
+    {file = "protobuf-6.31.1-cp39-cp39-win32.whl", hash = "sha256:0414e3aa5a5f3ff423828e1e6a6e907d6c65c1d5b7e6e975793d5590bdeecc16"},
+    {file = "protobuf-6.31.1-cp39-cp39-win_amd64.whl", hash = "sha256:8764cf4587791e7564051b35524b72844f845ad0bb011704c3736cce762d8fe9"},
+    {file = "protobuf-6.31.1-py3-none-any.whl", hash = "sha256:720a6c7e6b77288b85063569baae8536671b39f15cc22037ec7045658d80489e"},
+    {file = "protobuf-6.31.1.tar.gz", hash = "sha256:d8cac4c982f0b957a4dc73a80e2ea24fab08e679c0de9deb835f4a12d69aca9a"},
+]
+
 [[package]]
 name = "psycopg2-binary"
 version = "2.9.10"
@@ -2675,6 +2880,33 @@ files = [
     {file = "psycopg2_binary-2.9.10-cp39-cp39-win_amd64.whl", hash = "sha256:30e34c4e97964805f715206c7b789d54a78b70f3ff19fbe590104b71c45600e5"},
 ]
 
+[[package]]
+name = "pyasn1"
+version = "0.6.1"
+description = "Pure-Python implementation of ASN.1 types and DER/BER/CER codecs (X.208)"
+optional = false
+python-versions = ">=3.8"
+groups = ["main"]
+files = [
+    {file = "pyasn1-0.6.1-py3-none-any.whl", hash = "sha256:0d632f46f2ba09143da3a8afe9e33fb6f92fa2320ab7e886e2d0f7672af84629"},
+    {file = "pyasn1-0.6.1.tar.gz", hash = "sha256:6f580d2bdd84365380830acf45550f2511469f673cb4a5ae3857a3170128b034"},
+]
+
+[[package]]
+name = "pyasn1-modules"
+version = "0.4.2"
+description = "A collection of ASN.1-based protocols modules"
+optional = false
+python-versions = ">=3.8"
+groups = ["main"]
+files = [
+    {file = "pyasn1_modules-0.4.2-py3-none-any.whl", hash = "sha256:29253a9207ce32b64c3ac6600edc75368f98473906e8fd1043bd6b5b1de2c14a"},
+    {file = "pyasn1_modules-0.4.2.tar.gz", hash = "sha256:677091de870a80aae844b1ca6134f54652fa2c8c5a52aa396440ac3106e941e6"},
+]
+
+[package.dependencies]
+pyasn1 = ">=0.6.1,<0.7.0"
+
 [[package]]
 name = "pycparser"
 version = "2.22"
@@ -2927,6 +3159,21 @@ cffi = ">=1.4.1"
 docs = ["sphinx (>=1.6.5)", "sphinx-rtd-theme"]
 tests = ["hypothesis (>=3.27.0)", "pytest (>=3.2.1,!=3.3.0)"]
 
+[[package]]
+name = "pyparsing"
+version = "3.2.3"
+description = "pyparsing module - Classes and methods to define and execute parsing grammars"
+optional = false
+python-versions = ">=3.9"
+groups = ["main"]
+files = [
+    {file = "pyparsing-3.2.3-py3-none-any.whl", hash = "sha256:a749938e02d6fd0b59b356ca504a24982314bb090c383e3cf201c95ef7e2bfcf"},
+    {file = "pyparsing-3.2.3.tar.gz", hash = "sha256:b9c13f1ab8b3b542f72e28f634bad4de758ab3ce4546e4301970ad6fa77c38be"},
+]
+
+[package.extras]
+diagrams = ["jinja2", "railroad-diagrams"]
+
 [[package]]
 name = "pytest"
 version = "8.4.1"
@@ -3402,6 +3649,25 @@ urllib3 = ">=1.21.1,<3"
 socks = ["PySocks (>=1.5.6,!=1.5.7)"]
 use-chardet-on-py3 = ["chardet (>=3.0.2,<6)"]
 
+[[package]]
+name = "requests-oauthlib"
+version = "2.0.0"
+description = "OAuthlib authentication support for Requests."
+optional = false
+python-versions = ">=3.4"
+groups = ["main"]
+files = [
+    {file = "requests-oauthlib-2.0.0.tar.gz", hash = "sha256:b3dffaebd884d8cd778494369603a9e7b58d29111bf6b41bdc2dcd87203af4e9"},
+    {file = "requests_oauthlib-2.0.0-py2.py3-none-any.whl", hash = "sha256:7dd8a5c40426b779b0868c404bdef9768deccf22749cde15852df527e6269b36"},
+]
+
+[package.dependencies]
+oauthlib = ">=3.0.0"
+requests = ">=2.0.0"
+
+[package.extras]
+rsa = ["oauthlib[signedtoken] (>=3.0.0)"]
+
 [[package]]
 name = "requests-toolbelt"
 version = "1.0.0"
@@ -3582,6 +3848,21 @@ files = [
     {file = "rpds_py-0.27.0.tar.gz", hash = "sha256:8b23cf252f180cda89220b378d917180f29d313cd6a07b2431c0d3b776aae86f"},
 ]
 
+[[package]]
+name = "rsa"
+version = "4.9.1"
+description = "Pure-Python RSA implementation"
+optional = false
+python-versions = "<4,>=3.6"
+groups = ["main"]
+files = [
+    {file = "rsa-4.9.1-py3-none-any.whl", hash = "sha256:68635866661c6836b8d39430f97a996acbd61bfa49406748ea243539fe239762"},
+    {file = "rsa-4.9.1.tar.gz", hash = "sha256:e7bdbfdb5497da4c07dfd35530e1a902659db6ff241e39d9953cad06ebd0ae75"},
+]
+
+[package.dependencies]
+pyasn1 = ">=0.1.3"
+
 [[package]]
 name = "ruff"
 version = "0.12.9"
@@ -3749,6 +4030,62 @@ optional = false
 python-versions = ">=3.7"
 groups = ["main"]
 files = [
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+    {file = "SQLAlchemy-2.0.43-cp37-cp37m-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:11b9503fa6f8721bef9b8567730f664c5a5153d25e247aadc69247c4bc605227"},
+    {file = "SQLAlchemy-2.0.43-cp37-cp37m-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:07097c0a1886c150ef2adba2ff7437e84d40c0f7dcb44a2c2b9c905ccfc6361c"},
+    {file = "SQLAlchemy-2.0.43-cp37-cp37m-musllinux_1_2_aarch64.whl", hash = "sha256:cdeff998cb294896a34e5b2f00e383e7c5c4ef3b4bfa375d9104723f15186443"},
+    {file = "SQLAlchemy-2.0.43-cp37-cp37m-musllinux_1_2_x86_64.whl", hash = "sha256:bcf0724a62a5670e5718957e05c56ec2d6850267ea859f8ad2481838f889b42c"},
+    {file = "SQLAlchemy-2.0.43-cp37-cp37m-win32.whl", hash = "sha256:c697575d0e2b0a5f0433f679bda22f63873821d991e95a90e9e52aae517b2e32"},
+    {file = "SQLAlchemy-2.0.43-cp37-cp37m-win_amd64.whl", hash = "sha256:d34c0f6dbefd2e816e8f341d0df7d4763d382e3f452423e752ffd1e213da2512"},
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+    {file = "sqlalchemy-2.0.43-cp310-cp310-win_amd64.whl", hash = "sha256:4bf0edb24c128b7be0c61cd17eef432e4bef507013292415f3fb7023f02b7d4b"},
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+    {file = "sqlalchemy-2.0.43-cp38-cp38-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:136063a68644eca9339d02e6693932116f6a8591ac013b0014479a1de664e40a"},
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+    {file = "sqlalchemy-2.0.43-cp39-cp39-musllinux_1_2_aarch64.whl", hash = "sha256:03d73ab2a37d9e40dec4984d1813d7878e01dbdc742448d44a7341b7a9f408c7"},
+    {file = "sqlalchemy-2.0.43-cp39-cp39-musllinux_1_2_x86_64.whl", hash = "sha256:8cee08f15d9e238ede42e9bbc1d6e7158d0ca4f176e4eab21f88ac819ae3bd7b"},
+    {file = "sqlalchemy-2.0.43-cp39-cp39-win32.whl", hash = "sha256:b3edaec7e8b6dc5cd94523c6df4f294014df67097c8217a89929c99975811414"},
+    {file = "sqlalchemy-2.0.43-cp39-cp39-win_amd64.whl", hash = "sha256:227119ce0a89e762ecd882dc661e0aa677a690c914e358f0dd8932a2e8b2765b"},
+    {file = "sqlalchemy-2.0.43-py3-none-any.whl", hash = "sha256:1681c21dd2ccee222c2fe0bef671d1aef7c504087c9c4e800371cfcc8ac966fc"},
     {file = "sqlalchemy-2.0.43.tar.gz", hash = "sha256:788bfcef6787a7764169cfe9859fe425bf44559619e1d9f56f5bddf2ebf6f417"},
 ]
 
@@ -3966,6 +4303,18 @@ files = [
     {file = "tzdata-2025.2.tar.gz", hash = "sha256:b60a638fcc0daffadf82fe0f57e53d06bdec2f36c4df66280ae79bce6bd6f2b9"},
 ]
 
+[[package]]
+name = "uritemplate"
+version = "4.2.0"
+description = "Implementation of RFC 6570 URI Templates"
+optional = false
+python-versions = ">=3.9"
+groups = ["main"]
+files = [
+    {file = "uritemplate-4.2.0-py3-none-any.whl", hash = "sha256:962201ba1c4edcab02e60f9a0d3821e82dfc5d2d6662a21abd533879bdb8a686"},
+    {file = "uritemplate-4.2.0.tar.gz", hash = "sha256:480c2ed180878955863323eea31b0ede668795de182617fef9c6ca09e6ec9d0e"},
+]
+
 [[package]]
 name = "urllib3"
 version = "2.5.0"
@@ -4254,4 +4603,4 @@ cffi = ["cffi (>=1.17) ; python_version >= \"3.13\" and platform_python_implemen
 [metadata]
 lock-version = "2.1"
 python-versions = "^3.13"
-content-hash = "52c97a78f5d6a7d2367d6bb92032038024f09b8dc3a32e156fdb0c793fff63ec"
+content-hash = "2012735a4addfeab3c2c0b209539d224b8367d5801e9f36dc96e63eaf202366c"
diff --git a/backend/pyproject.toml b/backend/pyproject.toml
index 770bbe8c16..6269e07289 100644
--- a/backend/pyproject.toml
+++ b/backend/pyproject.toml
@@ -22,6 +22,9 @@ django-redis = "^6.0.0"
 django-storages = { extras = [ "s3" ], version = "^1.14.4" }
 emoji = "^2.14.1"
 geopy = "^2.4.1"
+google-api-python-client = "^2.178.0"
+google-auth-httplib2 = "^0.2.0"
+google-auth-oauthlib = "^1.2.2"
 gunicorn = "^23.0.0"
 humanize = "^4.11.0"
 jinja2 = "^3.1.6"
diff --git a/backend/settings/base.py b/backend/settings/base.py
index b00a731afb..5dbc383264 100644
--- a/backend/settings/base.py
+++ b/backend/settings/base.py
@@ -19,6 +19,14 @@ class Base(Configuration):
     DEBUG = False
     GITHUB_APP_ID = None
     GITHUB_APP_INSTALLATION_ID = None
+    GOOGLE_AUTH_AUTH_URI = values.Value()
+    GOOGLE_AUTH_CLIENT_ID = values.SecretValue()
+    GOOGLE_AUTH_CLIENT_SECRET = values.SecretValue()
+    GOOGLE_AUTH_REDIRECT_URI = values.Value()
+    GOOGLE_AUTH_SCOPES = values.ListValue()
+    GOOGLE_AUTH_TOKEN_URI = values.Value()
+
+    IS_GOOGLE_AUTH_ENABLED = values.BooleanValue(default=False)
     IS_LOCAL_ENVIRONMENT = False
     IS_PRODUCTION_ENVIRONMENT = False
     IS_STAGING_ENVIRONMENT = False
diff --git a/backend/tests/apps/nest/models/member_google_credentials_test.py b/backend/tests/apps/nest/models/member_google_credentials_test.py
new file mode 100644
index 0000000000..54a77a929e
--- /dev/null
+++ b/backend/tests/apps/nest/models/member_google_credentials_test.py
@@ -0,0 +1,325 @@
+"""Tests for MemberGoogleCredentials model."""
+
+from datetime import timedelta
+from unittest.mock import Mock, patch
+
+import pytest
+from django.conf import settings
+from django.core.exceptions import ValidationError
+from django.test import override_settings
+from django.utils import timezone
+from google_auth_oauthlib.flow import Flow
+
+from apps.nest.models.member_google_credentials import MemberGoogleCredentials
+from apps.slack.models.member import Member
+
+
+class TestMemberGoogleCredentialsModel:
+    """Test cases for MemberGoogleCredentials model."""
+
+    @pytest.fixture(autouse=True)
+    def setUp(self):
+        """Set up test data."""
+        self.member = Member(slack_user_id="U123456789", username="testuser")
+        self.valid_token = b"valid_token"
+        self.valid_refresh_token = b"valid_refresh_token"
+        self.expired_time = timezone.now() - timedelta(hours=1)
+        self.future_time = timezone.now() + timedelta(hours=1)
+
+    def test_member_google_credentials_creation(self):
+        """Test MemberGoogleCredentials model creation."""
+        auth = MemberGoogleCredentials(
+            member=self.member,
+            access_token=self.valid_token,
+            refresh_token=self.valid_refresh_token,
+            expires_at=self.future_time,
+        )
+
+        assert auth.member == self.member
+        assert auth.access_token == self.valid_token
+        assert auth.refresh_token == self.valid_refresh_token
+        assert auth.expires_at == self.future_time
+
+    def test_string_representation(self):
+        """Test string representation of MemberGoogleCredentials."""
+        auth = MemberGoogleCredentials(member=self.member, access_token=self.valid_token)
+
+        expected = f"MemberGoogleCredentials(member={self.member})"
+        assert str(auth) == expected
+
+    def test_one_to_one_relationship(self):
+        """Test one-to-one relationship with Member."""
+        auth = MemberGoogleCredentials(member=self.member, access_token=self.valid_token)
+
+        assert self.member.member_google_credentials == auth
+        assert auth.member == self.member
+
+    def test_is_token_expired_with_future_expiry(self):
+        """Test is_token_expired property with future expiry."""
+        auth = MemberGoogleCredentials(
+            member=self.member, access_token=self.valid_token, expires_at=self.future_time
+        )
+
+        assert not auth.is_token_expired
+
+    def test_is_token_expired_with_past_expiry(self):
+        """Test is_token_expired property with past expiry."""
+        auth = MemberGoogleCredentials(
+            member=self.member, access_token=self.valid_token, expires_at=self.expired_time
+        )
+
+        assert auth.is_token_expired
+
+    def test_is_token_expired_with_none_expiry(self):
+        """Test is_token_expired property with None expiry."""
+        auth = MemberGoogleCredentials(
+            member=self.member, access_token=self.valid_token, expires_at=None
+        )
+
+        assert auth.is_token_expired
+
+    @override_settings(IS_GOOGLE_AUTH_ENABLED=False)
+    def test_get_flow_when_disabled(self):
+        """Test get_flow raises error when Google auth is disabled."""
+        with pytest.raises(ValueError, match="Google OAuth client ID"):
+            MemberGoogleCredentials.get_flow()
+
+    @override_settings(IS_GOOGLE_AUTH_ENABLED=False)
+    def test_authenticate_when_disabled(self):
+        """Test authenticate raises error when Google auth is disabled."""
+        with pytest.raises(ValueError, match="Google OAuth client ID"):
+            MemberGoogleCredentials.authenticate(self.member)
+
+    @override_settings(
+        IS_GOOGLE_AUTH_ENABLED=True,
+        GOOGLE_AUTH_CLIENT_ID="test_client_id",
+        GOOGLE_AUTH_CLIENT_SECRET="test_client_secret",  # noqa: S106
+        GOOGLE_AUTH_REDIRECT_URI="http://localhost:8000/callback",
+    )
+    @patch("apps.nest.models.member_google_credentials.MemberGoogleCredentials.save")
+    @patch(
+        "apps.nest.models.member_google_credentials.MemberGoogleCredentials.objects.get_or_create"
+    )
+    @patch("apps.nest.models.member_google_credentials.MemberGoogleCredentials.get_flow")
+    def test_authenticate_existing_valid_token(self, mock_get_flow, mock_get_or_create, mock_save):
+        """Test authenticate with existing valid token."""
+        # Create existing auth with valid token
+
+        mock_get_flow.return_value = Mock(spec=Flow)
+        mock_get_or_create.return_value = (
+            MemberGoogleCredentials(
+                member=self.member,
+                access_token=self.valid_token,
+                refresh_token=self.valid_refresh_token,
+                expires_at=self.future_time,
+            ),
+            True,
+        )
+        result = MemberGoogleCredentials.authenticate(self.member)
+
+        assert result.access_token == self.valid_token
+        assert result.refresh_token == self.valid_refresh_token
+        assert result.expires_at == self.future_time
+        mock_get_or_create.assert_called_once_with(member=self.member)
+        mock_save.assert_not_called()
+
+    @override_settings(
+        IS_GOOGLE_AUTH_ENABLED=True,
+        GOOGLE_AUTH_CLIENT_ID="test_client_id",
+        GOOGLE_AUTH_CLIENT_SECRET="test_client_secret",  # noqa: S106
+        GOOGLE_AUTH_REDIRECT_URI="http://localhost:8000/callback",
+    )
+    @patch(
+        "apps.nest.models.member_google_credentials.MemberGoogleCredentials.refresh_access_token"
+    )
+    @patch(
+        "apps.nest.models.member_google_credentials.MemberGoogleCredentials.objects.get_or_create"
+    )
+    def test_authenticate_existing_expired_token(self, mock_get_or_create, mock_refresh):
+        """Test authenticate with existing expired token."""
+        # Create existing auth with expired token
+        existing_auth = MemberGoogleCredentials(
+            member=self.member,
+            access_token=self.valid_token,
+            refresh_token=self.valid_refresh_token,
+            expires_at=self.expired_time,
+        )
+        mock_get_or_create.return_value = (existing_auth, False)
+
+        MemberGoogleCredentials.authenticate(self.member)
+
+        mock_refresh.assert_called_once_with(existing_auth)
+        mock_get_or_create.assert_called_once_with(member=self.member)
+
+    @override_settings(
+        IS_GOOGLE_AUTH_ENABLED=True,
+        GOOGLE_AUTH_CLIENT_ID="test_client_id",
+        GOOGLE_AUTH_CLIENT_SECRET="test_client_secret",  # noqa: S106
+        GOOGLE_AUTH_REDIRECT_URI="http://localhost:8000/callback",
+    )
+    @patch("apps.nest.models.member_google_credentials.MemberGoogleCredentials.get_flow")
+    @patch(
+        "apps.nest.models.member_google_credentials.MemberGoogleCredentials.objects.get_or_create"
+    )
+    def test_authenticate_first_time(self, mock_get_or_create, mock_get_flow):
+        """Test authenticate for first time (no existing token)."""
+        # Mock flow and credentials
+        mock_flow_instance = Mock()
+        mock_get_flow.return_value = mock_flow_instance
+        mock_get_or_create.return_value = (
+            MemberGoogleCredentials(
+                member=self.member,
+                access_token=None,
+                refresh_token=None,
+                expires_at=None,
+            ),
+            True,
+        )
+        MemberGoogleCredentials.authenticate(self.member)
+
+        mock_get_or_create.assert_called_once_with(member=self.member)
+
+        mock_flow_instance.authorization_url.assert_called_once_with(
+            access_type="offline",
+            prompt="consent",
+            state=self.member.slack_user_id,
+        )
+
+    @override_settings(IS_GOOGLE_AUTH_ENABLED=False)
+    def test_refresh_access_token_when_disabled(self):
+        """Test refresh_access_token raises error when Google auth is disabled."""
+        auth = MemberGoogleCredentials(
+            member=self.member,
+            access_token=self.valid_token,
+            refresh_token=self.valid_refresh_token,
+        )
+
+        with pytest.raises(ValueError, match="Google OAuth client ID"):
+            MemberGoogleCredentials.refresh_access_token(auth)
+
+    @override_settings(
+        IS_GOOGLE_AUTH_ENABLED=True,
+        GOOGLE_AUTH_CLIENT_ID="test_client_id",
+        GOOGLE_AUTH_CLIENT_SECRET="test_client_secret",  # noqa: S106
+        GOOGLE_AUTH_REDIRECT_URI="http://localhost:8000/callback",
+    )
+    @patch("apps.nest.models.member_google_credentials.Credentials")
+    @patch("apps.nest.models.member_google_credentials.Request")
+    @patch("apps.nest.models.member_google_credentials.MemberGoogleCredentials.save")
+    def test_refresh_access_token_success(self, mock_save, mock_request, mock_credentials):
+        """Test successful refresh_access_token."""
+        # Create auth with refresh token
+        auth = MemberGoogleCredentials(
+            member=self.member,
+            access_token=self.valid_token,
+            refresh_token=self.valid_refresh_token,
+            expires_at=self.expired_time,
+        )
+
+        # Mock flow and new credentials
+        mock_credentials_instance = Mock()
+        mock_credentials_instance.token = b"token"  # NOSONAR
+        mock_credentials_instance.refresh_token = b"refresh_token"
+        mock_credentials_instance.expiry = self.future_time
+
+        mock_credentials.return_value = mock_credentials_instance
+
+        MemberGoogleCredentials.refresh_access_token(auth)
+
+        assert auth.access_token == b"token"
+        assert auth.refresh_token == b"refresh_token"
+        assert auth.expires_at == self.future_time
+
+        mock_credentials.assert_called_once_with(
+            token=self.valid_token,
+            refresh_token=self.valid_refresh_token,
+            token_uri=settings.GOOGLE_AUTH_TOKEN_URI,
+            client_id=settings.GOOGLE_AUTH_CLIENT_ID,
+            client_secret=settings.GOOGLE_AUTH_CLIENT_SECRET,
+        )
+        mock_credentials_instance.refresh.assert_called_once_with(mock_request.return_value)
+        mock_save.assert_called_once()
+
+    @override_settings(
+        IS_GOOGLE_AUTH_ENABLED=True,
+        GOOGLE_AUTH_CLIENT_ID="test_client_id",
+        GOOGLE_AUTH_CLIENT_SECRET="test_client_secret",  # noqa: S106
+        GOOGLE_AUTH_REDIRECT_URI="http://localhost:8000/callback",
+    )
+    def test_refresh_token_not_found(self):
+        """Test refresh_access_token raises error when no refresh token is present."""
+        auth = MemberGoogleCredentials(
+            member=self.member,
+            access_token=self.valid_token,
+            refresh_token=None,
+        )
+
+        with pytest.raises(
+            ValidationError, match="Google OAuth refresh token is not set or expired."
+        ):
+            MemberGoogleCredentials.refresh_access_token(auth)
+
+    def test_verbose_names(self):
+        """Test model field verbose names."""
+        auth = MemberGoogleCredentials(member=self.member, access_token=self.valid_token)
+
+        assert auth._meta.get_field("member").verbose_name == "Slack Member"
+        assert auth._meta.get_field("access_token").verbose_name == "Access Token"
+        assert auth._meta.get_field("refresh_token").verbose_name == "Refresh Token"
+        assert auth._meta.get_field("expires_at").verbose_name == "Token Expiry"
+
+    @override_settings(IS_GOOGLE_AUTH_ENABLED=False)
+    def test_authenticate_callback_member_google_credentials_disabled(self):
+        """Test authenticate_callback raises error when Google auth is disabled."""
+        with pytest.raises(ValueError, match="Google OAuth client ID"):
+            MemberGoogleCredentials.authenticate_callback(auth_response={}, member_id=4)
+
+    @override_settings(
+        IS_GOOGLE_AUTH_ENABLED=True,
+        GOOGLE_AUTH_CLIENT_ID="test_client_id",
+        GOOGLE_AUTH_CLIENT_SECRET="test_client_secret",  # noqa: S106
+        GOOGLE_AUTH_REDIRECT_URI="http://localhost:8000/callback",
+    )
+    @patch("apps.nest.models.member_google_credentials.MemberGoogleCredentials.get_flow")
+    @patch(
+        "apps.nest.models.member_google_credentials.MemberGoogleCredentials.objects.get_or_create"
+    )
+    @patch("apps.nest.models.member_google_credentials.MemberGoogleCredentials.save")
+    @patch("apps.nest.models.member_google_credentials.Member.objects.get")
+    def test_authenticate_callback_success(
+        self, mock_member_get, mock_save, mock_get_or_create, mock_get_flow
+    ):
+        """Test successful authenticate_callback."""
+        mock_credentials = Mock()
+        mock_credentials.token = b"token"  # NOSONAR
+        mock_credentials.refresh_token = b"refresh_token"
+        mock_credentials.expiry = self.future_time
+
+        mock_flow_instance = Mock(spec=Flow)
+        mock_flow_instance.credentials = mock_credentials
+        mock_member_get.return_value = self.member
+        mock_get_flow.return_value = mock_flow_instance
+        mock_get_or_create.return_value = (MemberGoogleCredentials(member=self.member), False)
+        result = MemberGoogleCredentials.authenticate_callback(
+            {}, member_id=self.member.slack_user_id
+        )
+
+        assert result.access_token == b"token"
+        assert result.refresh_token == b"refresh_token"
+        assert result.expires_at == self.future_time
+        mock_get_or_create.assert_called_once_with(member=self.member)
+        mock_save.assert_called_once()
+        mock_flow_instance.fetch_token.assert_called_once_with(authorization_response={})
+
+    @override_settings(
+        IS_GOOGLE_AUTH_ENABLED=True,
+        GOOGLE_AUTH_CLIENT_ID="test_client_id",
+        GOOGLE_AUTH_CLIENT_SECRET="test_client_secret",  # noqa: S106
+        GOOGLE_AUTH_REDIRECT_URI="http://localhost:8000/callback",
+    )
+    @patch("apps.slack.models.member.Member.objects.get")
+    def test_authenticate_callback_member_not_found(self, mock_member_get):
+        """Test authenticate_callback raises error when member is not found."""
+        mock_member_get.side_effect = Member.DoesNotExist
+        with pytest.raises(ValidationError, match="Member with Slack ID 4 does not exist."):
+            MemberGoogleCredentials.authenticate_callback(auth_response={}, member_id=4)