diff --git a/.github/scripts/test_dependency_compatibility.sh b/.github/scripts/test_dependency_compatibility.sh
new file mode 100755
index 0000000000..f2a5ae638e
--- /dev/null
+++ b/.github/scripts/test_dependency_compatibility.sh
@@ -0,0 +1,99 @@
+#!/bin/bash
+
+# This script generates a maven command to test unit and integration tests for
+# the repo. The outputted maven command will be in the rough following format
+# `mvn verify ... -D{dependency.name}.version={dependency.version]`. The variables
+# ${dependency.name} and ${dependency.version} are parsed from the input to the script.
+#
+# Default invocation ./.github/scripts/test_dependency_compatibility.sh will use the default
+# upper-bounds dependency file at the root of the repo.
+# There are two potential inputs to the script:
+# 1. -f {file}: Custom file/path for the upper-bound dependencies to test
+# 2. -l {deps_list}: Comma-separated list of dependencies to test (e.g. protobuf=4.31.0,guava=33.4.8-jre)
+# Note: Do not include the `-D` prefix or `.version` suffix. Those values will be appended when generating
+# the maven command.
+#
+# If both inputs are supplied, the deps_list input has precedence. For Github Actions workflow,
+# the default workflow will run with the upper-bounds file. A `workflow_dispatch` option takes in
+# an input for the deps_list to manually run a subset of dependencies.
+#
+# The default upper-bound dependencies file is `dependencies.txt` located in the root
+# of sdk-platform-java. The upper-bound dependencies file will be in the format of:
+# ${dependency.name}=${dependency.version}
+
+set -ex
+
+function print_help() {
+  echo "Unexpected input argument for this script."
+  echo "Use -f {file} for the directory of the upper-bound dependencies file."
+  echo "Use -l {deps_list} for a comma-separated list of dependencies to test (Format: dep1=1.0,dep2=2.0)"
+}
+
+# Function to parse a dependency string and append it to the Maven command
+function add_dependency_to_maven_command() {
+  local dep_pair=$1
+  if [[ ! "${dep_pair}" =~ .*=.* ]]; then
+    echo "Malformed dependency string: ${dep_pair}. Expected format: dependency=version"
+    exit 1
+  fi
+  local dependency=$(echo "${dep_pair}" | cut -d'=' -f1 | tr -d '[:space:]')
+  local version=$(echo "${dep_pair}" | cut -d'=' -f2 | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')
+  MAVEN_COMMAND+=" -D${dependency}.version=${version}"
+}
+
+# Default to the upper bounds file in the root of the repo
+file='dependencies.txt'
+dependency_list=''
+
+# The colon (:) after the letter means that there is an input associated with the flag
+while getopts 'f:l:' flag; do
+  case "${flag}" in
+    f) file="${OPTARG}" ;;
+    l) dependency_list="${OPTARG}" ;;
+    *) print_help && exit 1
+  esac
+done
+
+# Error if both the file and deps_list inputs is empty
+if [[ -z "${file}" && -z "${dependency_list}" ]]; then
+  print_help && exit 1
+fi
+
+MAVEN_COMMAND="mvn verify -Penable-integration-tests -Dclirr.skip -Dcheckstyle.skip -Dfmt.skip -Denforcer.skip "
+
+# Check if a list of dependencies was provided as an argument. If the list of dependency inputted
+# is empty, then run with the upper-bound dependencies file
+if [ -z "${dependency_list}" ]; then
+  UPPER_BOUND_DEPENDENCY_FILE=$file
+
+  if [ ! -e "${UPPER_BOUND_DEPENDENCY_FILE}" ]; then
+    echo "The inputted upper-bound dependency file '${UPPER_BOUND_DEPENDENCY_FILE}' cannot be found"
+    exit 1
+  fi
+
+  # Read the file line by line
+  while IFS= read -r line; do
+    # Ignore any comments and blank lines
+    if [[ "${line}" =~ ^[[:space:]]*# ]] || [[ -z "${line}" ]]; then
+      continue
+    fi
+    add_dependency_to_maven_command "${line}"
+  done < "${UPPER_BOUND_DEPENDENCY_FILE}"
+else # This else block means that a list of dependencies was inputted
+  # Set the Internal Field Separator (IFS) to a comma.
+  # This tells 'read' to split the string by commas into an array named DEPS.
+  # The 'read -ra' command reads the input into an array.
+  IFS=',' read -ra DEPS <<< "${dependency_list}"
+
+  # Loop through each item in the DEPS array.
+  for DEP_PAIR in "${DEPS[@]}"; do
+    # Skip any empty items that might result from trailing commas.
+    if [ -z "${DEP_PAIR}" ]; then
+      continue
+    fi
+    add_dependency_to_maven_command "${DEP_PAIR}"
+  done
+fi
+
+# Run the generated maven command to test with the dependency versions
+$MAVEN_COMMAND
diff --git a/.github/workflows/dependency_compatibility_test.yaml b/.github/workflows/dependency_compatibility_test.yaml
new file mode 100644
index 0000000000..f3aaee350c
--- /dev/null
+++ b/.github/workflows/dependency_compatibility_test.yaml
@@ -0,0 +1,72 @@
+name: Dependency Compatibility Test
+
+on:
+  pull_request:
+    branches:
+      - 'main'
+  workflow_dispatch:
+    inputs:
+      dependencies-list:
+        description: 'Comma-separated list of dependencies to test (Example format: protobuf=4.31.0,guava=33.4.8-jre).
+                      Do not include the `-D` prefix or `.version` suffix. Those values will be appended when generating
+                      the command. No input (default) will run the the upper-bound dependencies file.'
+        required: false
+        default: ''
+
+jobs:
+  dependency-compatibility-test:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout sdk-platform-java
+        uses: actions/checkout@v4
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+          cache: maven
+      # The workflow_dispatch event is for team members who want to manually test certain dependencies + version combos
+      # The normal workflow is not from `workflow_dispatch` and will use the default upper-bounds dependencies file
+      - name: Determine Inputted Dependencies List
+        if: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.dependencies-list != '' }}
+        run: echo "DEPENDENCIES_LIST=${{ github.event.inputs.dependencies-list }}" >> $GITHUB_ENV
+      # Install the modules for the rest of the CI
+      - name: Install sdk-platform-java's modules
+        # gapic-generator-java requires Java 8 and is irrelevant for this CI
+        run: mvn -q -B -ntp install --projects '!gapic-generator-java' -Dcheckstyle.skip -Dfmt.skip -DskipTests -Dclirr.skip -T 1C
+
+      # Run in the root module which should test for everything except for showcase
+      - name: Perform Dependency Compatibility Testing
+        shell: bash
+        run: |
+          if [[ -n "${{ env.DEPENDENCIES_LIST }}" ]]; then
+            ./.github/scripts/test_dependency_compatibility.sh -l ${{ env.DEPENDENCIES_LIST }}
+          else
+            ./.github/scripts/test_dependency_compatibility.sh
+          fi
+      # Set up local showcase server to run the showcase ITs
+      - name: Parse showcase version
+        working-directory: java-showcase/gapic-showcase
+        run: echo "SHOWCASE_VERSION=$(mvn help:evaluate -Dexpression=gapic-showcase.version -q -DforceStdout)" >> "$GITHUB_ENV"
+      - name: Install showcase server
+        run: |
+          sudo mkdir -p /usr/src/showcase
+          sudo chown -R ${USER} /usr/src/
+          curl --location https://github.com/googleapis/gapic-showcase/releases/download/v${{env.SHOWCASE_VERSION}}/gapic-showcase-${{env.SHOWCASE_VERSION}}-linux-amd64.tar.gz --output /usr/src/showcase/showcase-${{env.SHOWCASE_VERSION}}-linux-amd64.tar.gz
+          cd /usr/src/showcase/
+          tar -xf showcase-*
+          ./gapic-showcase run &
+          cd -
+      # Run specifically for showcase
+      - name: Perform Dependency Compatibility Testing (Showcase only)
+        shell: bash
+        # Need to cd out of the directory to get the scripts as this step is run inside the java-showcase directory
+        run: |
+          if [[ -n "${{ env.DEPENDENCIES_LIST }}" ]]; then
+            ../.github/scripts/test_dependency_compatibility.sh -l ${{ env.DEPENDENCIES_LIST }}
+          else
+            ../.github/scripts/test_dependency_compatibility.sh -f ../dependencies.txt
+          fi
+        working-directory: java-showcase
diff --git a/dependencies.txt b/dependencies.txt
new file mode 100644
index 0000000000..317b88ea1d
--- /dev/null
+++ b/dependencies.txt
@@ -0,0 +1,42 @@
+# This file contains a list of dependencies and their versions to be tested for compatibility.
+# The format is key=value, where the key is the dependency name and the value is the version.
+# "1P" refers to First-Party dependencies (owned by Google).
+# "3P" refers to Third-Party dependencies.
+
+# 1P Parent-Pom
+javax.annotation-api=1.3.2
+grpc=1.74.0
+google.auth=1.37.1
+google.http-client=1.47.1
+gson=2.13.1
+guava=33.4.8-jre
+protobuf=4.31.1
+opentelemetry=1.52.0
+errorprone=2.41.0
+j2objc-annotations=3.0.0
+threetenbp=1.7.1
+slf4j=2.0.17
+
+# 1P Shared-Deps
+grpc-gcp=1.6.1
+google.oauth-client=1.39.0
+google.api-client=2.8.0
+
+# 3P Shared-Deps
+threeten-extra=1.8.0
+opencensus=0.31.0
+findbugs=3.0.2
+jackson=2.19.2
+codec=1.19.0
+httpcomponents.httpcore=4.4.16
+httpcomponents.httpclient=4.5.14
+apache-httpclient-5=5.5
+apache-httpcore-5=5.3.4
+perfmark-api=0.27.0
+google.cloud.opentelemetry=0.36.0
+opentelemetry-semconv=1.34.0
+flogger=0.9
+arrow=18.3.0
+dev.cel=0.10.1
+com.google.crypto.tink=1.18.0
+io.opentelemetry.contrib.opentelemetry-gcp-resources=1.48.0-alpha