diff --git a/llama-index-integrations/tools/llama-index-tools-google/Makefile b/llama-index-integrations/tools/llama-index-tools-google/Makefile
index b9eab05aa3..653075c04e 100644
--- a/llama-index-integrations/tools/llama-index-tools-google/Makefile
+++ b/llama-index-integrations/tools/llama-index-tools-google/Makefile
@@ -3,6 +3,12 @@ GIT_ROOT ?= $(shell git rev-parse --show-toplevel)
 help:	## Show all Makefile targets.
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[33m%-30s\033[0m %s\n", $$1, $$2}'
 
+
+pre-commit: sync lint format test
+
+sync:
+	uv sync
+
 format:	## Run code autoformatters (black).
 	pre-commit install
 	git ls-files | xargs pre-commit run black --files
diff --git a/llama-index-integrations/tools/llama-index-tools-google/README.md b/llama-index-integrations/tools/llama-index-tools-google/README.md
index a721848f11..4796fe97c6 100644
--- a/llama-index-integrations/tools/llama-index-tools-google/README.md
+++ b/llama-index-integrations/tools/llama-index-tools-google/README.md
@@ -30,6 +30,20 @@ google_spec = GoogleSearchToolSpec(key="your-key", engine="your-engine")
 - store oAuth`credentials.json` in the same directory as the runnable agent.
 - you will need to manually approve the Oath every time this tool is invoked
 
+**Multi-calendar support:**
+
+```python
+from llama_index.tools.google import GoogleCalendarToolSpec, all_calendars
+
+# List all available calendars
+calendar_ids = all_calendars(creds)
+
+# Create tool spec with specific allowed calendars
+calendar_spec = GoogleCalendarToolSpec(
+    creds=creds, allowed_calendar_ids=calendar_ids
+)
+```
+
 #### [gmail read, create]()
 
 - same as calendar
diff --git a/llama-index-integrations/tools/llama-index-tools-google/llama_index/tools/google/__init__.py b/llama-index-integrations/tools/llama-index-tools-google/llama_index/tools/google/__init__.py
index cb7d77af25..ce881ba307 100644
--- a/llama-index-integrations/tools/llama-index-tools-google/llama_index/tools/google/__init__.py
+++ b/llama-index-integrations/tools/llama-index-tools-google/llama_index/tools/google/__init__.py
@@ -1,4 +1,4 @@
-from llama_index.tools.google.calendar.base import GoogleCalendarToolSpec
+from llama_index.tools.google.calendar.base import GoogleCalendarToolSpec, all_calendars
 from llama_index.tools.google.gmail.base import GmailToolSpec
 from llama_index.tools.google.search.base import (
     QUERY_URL_TMPL,
@@ -7,6 +7,7 @@
 
 __all__ = [
     "GoogleCalendarToolSpec",
+    "all_calendars",
     "GmailToolSpec",
     "GoogleSearchToolSpec",
     "QUERY_URL_TMPL",
diff --git a/llama-index-integrations/tools/llama-index-tools-google/llama_index/tools/google/calendar/base.py b/llama-index-integrations/tools/llama-index-tools-google/llama_index/tools/google/calendar/base.py
index afa34141fb..5e727ffdea 100644
--- a/llama-index-integrations/tools/llama-index-tools-google/llama_index/tools/google/calendar/base.py
+++ b/llama-index-integrations/tools/llama-index-tools-google/llama_index/tools/google/calendar/base.py
@@ -35,7 +35,11 @@ class GoogleCalendarToolSpec(BaseToolSpec):
 
     spec_functions = ["load_data", "create_event", "get_date"]
 
-    def __init__(self, creds: Optional[Any] = None):
+    def __init__(
+        self,
+        creds: Optional[Any] = None,
+        allowed_calendar_ids: Optional[List[str]] = None,
+    ):
         """
         Initialize the GoogleCalendarToolSpec.
 
@@ -45,11 +49,13 @@ def __init__(self, creds: Optional[Any] = None):
 
         """
         self.creds = creds
+        self.allowed_calendar_ids = allowed_calendar_ids or []
 
     def load_data(
         self,
         number_of_results: Optional[int] = 100,
         start_date: Optional[Union[str, datetime.date]] = None,
+        calendar_id: Optional[str] = None,
     ) -> List[Document]:
         """
         Load data from user's calendar.
@@ -57,8 +63,16 @@ def load_data(
         Args:
             number_of_results (Optional[int]): the number of events to return. Defaults to 100.
             start_date (Optional[Union[str, datetime.date]]): the start date to return events from in date isoformat. Defaults to today.
+            calendar_id (Optional[str]): the calendar ID to load events from. Must be provided and in allowed_calendar_ids list.
 
         """
+        if calendar_id is None:
+            return {"error": "calendar_id is required"}
+
+        validation_error = self._validate_calendar_id(calendar_id)
+        if validation_error:
+            return validation_error
+
         from googleapiclient.discovery import build
 
         credentials = self._get_credentials()
@@ -75,7 +89,7 @@ def load_data(
         events_result = (
             service.events()
             .list(
-                calendarId="primary",
+                calendarId=calendar_id,
                 timeMin=start_datetime_utc,
                 maxResults=number_of_results,
                 singleEvents=True,
@@ -164,6 +178,7 @@ def create_event(
         start_datetime: Optional[Union[str, datetime.datetime]] = None,
         end_datetime: Optional[Union[str, datetime.datetime]] = None,
         attendees: Optional[List[str]] = None,
+        calendar_id: Optional[str] = None,
     ) -> str:
         """
             Create an event on the users calendar.
@@ -175,8 +190,16 @@ def create_event(
             start_datetime Optional[Union[str, datetime.datetime]]: The start datetime for the event
             end_datetime Optional[Union[str, datetime.datetime]]: The end datetime for the event
             attendees Optional[List[str]]: A list of email address to invite to the event
+            calendar_id (Optional[str]): The calendar ID to create the event in. Must be provided and in allowed_calendar_ids list.
 
         """
+        if calendar_id is None:
+            return "Error: calendar_id is required"
+
+        validation_error = self._validate_calendar_id(calendar_id)
+        if validation_error:
+            return validation_error
+
         from googleapiclient.discovery import build
 
         credentials = self._get_credentials()
@@ -209,14 +232,37 @@ def create_event(
             },
             "attendees": attendees_list,
         }
-        event = service.events().insert(calendarId="primary", body=event).execute()
+        event = service.events().insert(calendarId=calendar_id, body=event).execute()
         return (
             "Your calendar event has been created successfully! You can move on to the"
             " next step."
         )
 
+    def _validate_calendar_id(self, calendar_id: str) -> dict:
+        if calendar_id not in self.allowed_calendar_ids:
+            import logging
+
+            logger = logging.getLogger(__name__)
+            logger.error(
+                f"Invalid calendar ID '{calendar_id}' attempted. Valid IDs: {self.allowed_calendar_ids}"
+            )
+            return {
+                "error": "Invalid calendar_id",
+                "allowed_values": list(self.allowed_calendar_ids),
+            }
+        return None
+
     def get_date(self):
         """
         A function to return todays date. Call this before any other functions if you are unaware of the date.
         """
         return datetime.date.today()
+
+
+def all_calendars(creds) -> List[str]:
+    """List all accessible calendar IDs for configuration purposes."""
+    from googleapiclient.discovery import build
+
+    service = build("calendar", "v3", credentials=creds)
+    calendar_list = service.calendarList().list().execute()
+    return [cal["id"] for cal in calendar_list.get("items", [])]
diff --git a/llama-index-integrations/tools/llama-index-tools-google/tests/test_tools_google.py b/llama-index-integrations/tools/llama-index-tools-google/tests/test_tools_google.py
index 0662e60bee..02cdf3f9a1 100644
--- a/llama-index-integrations/tools/llama-index-tools-google/tests/test_tools_google.py
+++ b/llama-index-integrations/tools/llama-index-tools-google/tests/test_tools_google.py
@@ -58,3 +58,29 @@ def test_google_calendar_tool_spec_get_credentials_oauth_flow(
     mock_from_file.assert_called_once_with(
         "token.json", ["https://www.googleapis.com/auth/calendar"]
     )
+
+
+def test_google_calendar_tool_spec_init_with_allowed_calendar_ids():
+    """Test GoogleCalendarToolSpec initialization with allowed calendar IDs."""
+    allowed_ids = ["test@example.com", "secondary@example.com"]
+    tool = GoogleCalendarToolSpec(allowed_calendar_ids=allowed_ids)
+    assert tool.allowed_calendar_ids == allowed_ids
+
+
+def test_calendar_id_validation_error():
+    """Test calendar ID validation returns structured error."""
+    allowed_ids = ["test@example.com"]
+    tool = GoogleCalendarToolSpec(allowed_calendar_ids=allowed_ids)
+
+    result = tool._validate_calendar_id("invalid@example.com")
+    expected = {"error": "Invalid calendar_id", "allowed_values": ["test@example.com"]}
+    assert result == expected
+
+
+def test_calendar_id_validation_success():
+    """Test calendar ID validation returns None for valid ID."""
+    allowed_ids = ["test@example.com", "secondary@example.com"]
+    tool = GoogleCalendarToolSpec(allowed_calendar_ids=allowed_ids)
+
+    result = tool._validate_calendar_id("test@example.com")
+    assert result is None