diff --git a/.github/workflows/gapic-generator-tests.yml b/.github/workflows/gapic-generator-tests.yml
index 6379fa492d41..e5029174f61d 100644
--- a/.github/workflows/gapic-generator-tests.yml
+++ b/.github/workflows/gapic-generator-tests.yml
@@ -19,10 +19,6 @@ env:
   PRERELEASE_PYTHON: 3.15
   ALL_PYTHON: "['3.10', '3.11', '3.12', '3.13', '3.14', '3.15']"
   TRIMMED_PYTHON: "['3.10', '3.14', '3.15']"
-  # Workaround: Allows libcst to compile on Python 3.15+ while PyO3 catches up
-  # Can be removed once libcst releases a version with native Python 3.15 wheels
-  # Follow https://github.com/Instagram/LibCST/issues/1445 for updates.
-  PYO3_USE_ABI3_FORWARD_COMPATIBILITY: "1"
 
 jobs:
   # Check if the gapic-generator was changed. If so, execute specialized tests
diff --git a/.github/workflows/import-profiler.yml b/.github/workflows/import-profiler.yml
index 33bf120a0e05..c527c1b43fe1 100644
--- a/.github/workflows/import-profiler.yml
+++ b/.github/workflows/import-profiler.yml
@@ -89,8 +89,6 @@ jobs:
         TARGET_BRANCH: ${{ github.base_ref || github.event.merge_group.base_ref }}
         TEST_TYPE: import_profile
         PY_VERSION: "3.15"
-        # Workaround: Allows libcst to compile on Python 3.15+ while PyO3 catches up
-        PYO3_USE_ABI3_FORWARD_COMPATIBILITY: "1"
         PACKAGE_LIST: ${{ matrix.package_shard.packages }}
       run: |
         ci/run_conditional_tests.sh
diff --git a/.github/workflows/prerelease-deps.yml b/.github/workflows/prerelease-deps.yml
index ba816dddbb25..a7098fbce4c2 100644
--- a/.github/workflows/prerelease-deps.yml
+++ b/.github/workflows/prerelease-deps.yml
@@ -36,8 +36,6 @@ env:
   PACKAGE_DIRS: packages
   NOX_DEFAULT_VENV_BACKEND: "virtualenv"
   UV_PRERELEASE: "allow"
-  # Workaround: Allows libcst/Rust extensions to compile on Python 3.15+ while PyO3 catches up
-  PYO3_USE_ABI3_FORWARD_COMPATIBILITY: "1"
 
 jobs:
   prerelease:
@@ -178,7 +176,11 @@ jobs:
           } >> "$GITHUB_OUTPUT"
 
       - name: Create issue on failure
-        if: ${{ steps.run-tests.outcome == 'failure' && github.repository == 'googleapis/google-cloud-python' }}
+        # Only file an issue from the nightly schedule or a manual dispatch, never from a
+        # pull request. PRs that touch `ci/**` or this workflow trigger the check for
+        # validation purposes only; filing a `priority: p1` issue from them would duplicate
+        # the nightly report. The job summary written above still surfaces PR failures.
+        if: ${{ steps.run-tests.outcome == 'failure' && github.event_name != 'pull_request' && github.repository == 'googleapis/google-cloud-python' }}
         uses: googleapis/librarian/.github/actions/create-issue-on-failure@bb2ee61752bd0f5387195b54c509e4d01a52b41d
         with:
           title: "prerelease_deps check failed"
diff --git a/.github/workflows/unittest.yml b/.github/workflows/unittest.yml
index 68ccc4969d7f..507aff5300b8 100644
--- a/.github/workflows/unittest.yml
+++ b/.github/workflows/unittest.yml
@@ -133,31 +133,6 @@ jobs:
     - name: Install nox and nox-uv
       run: |
         uv pip install --system nox nox-uv
-    # Caches local wheels for Python 3.15+ to avoid repeatedly downloading or building heavy libraries.
-    # Follow https://github.com/grpc/grpc/issues/41010 for updates.
-    - name: Cache Built Python 3.15 Wheels
-      if: matrix.python == '3.15'
-      uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4
-      with:
-        path: .uv-wheel-cache
-        key: ${{ runner.os }}-uv-wheels-3.15-${{ hashFiles('packages/**/testing/constraints*.txt') }}
-        restore-keys: |
-          ${{ runner.os }}-uv-wheels-3.15-
-    # TODO: Remove this step once official Python 3.15 wheels for grpcio are published to PyPI.
-    # See https://github.com/grpc/grpc/issues/41010#issuecomment-4848264910 for details.
-    - name: Install grpcio wheel for Python 3.15
-      if: matrix.python == '3.15'
-      run: |
-        mkdir -p .uv-wheel-cache
-        WHEEL_FILE=".uv-wheel-cache/grpcio-1.83.0.dev0-cp315-cp315-manylinux2014_x86_64.manylinux_2_17_x86_64.whl"
-        if [ ! -f "$WHEEL_FILE" ]; then
-          curl -L "https://packages.grpc.io/archive/2026/06/5ccdab32010f762634e1082d19be53cf60458456-b37e49c7-5e62-4cbe-870a-c599bb907b04/python/grpcio/grpcio-1.83.0.dev0-cp315-cp315-manylinux2014_x86_64.manylinux_2_17_x86_64.whl" -o "$WHEEL_FILE"
-        fi
-        echo "d7706633cd5d97a8b8d3c6ed36c5940722a9b5cbb47f0d10bc433ee27af36ff0  $WHEEL_FILE" | sha256sum -c
-        uv pip install --system "$WHEEL_FILE"
-        echo "UV_FIND_LINKS=${{ github.workspace }}/.uv-wheel-cache" >> $GITHUB_ENV
-        echo "UV_CACHE_DIR=${{ github.workspace }}/.uv-wheel-cache" >> $GITHUB_ENV
-        echo "UV_PRERELEASE=allow" >> $GITHUB_ENV
     - name: Run unit tests for ${{ matrix.package_shard.description }}
       env:
         BUILD_TYPE: presubmit
diff --git a/.librarian/generator-input/client-post-processing/bigtable-integration.yaml b/.librarian/generator-input/client-post-processing/bigtable-integration.yaml
index 16fdf18b574f..2ff18605f256 100644
--- a/.librarian/generator-input/client-post-processing/bigtable-integration.yaml
+++ b/.librarian/generator-input/client-post-processing/bigtable-integration.yaml
@@ -609,11 +609,6 @@ replacements:
       def unit(session, protobuf_implementation):
           # Install all test dependencies, then install this package in-place.
 
-          # TODO(https://github.com/googleapis/google-cloud-python/issues/17741):
-          # Remove once `google-crc32c` wheels are published for 3.15
-          if session.python == "3.15":
-              session.skip("Skipping 3.15 until wheels are available for google-crc32c.")
-
           constraints_path = str(
               CURRENT_DIRECTORY / "testing" / f"constraints-{session.python}.txt"
           )
diff --git a/packages/django-google-spanner/setup.py b/packages/django-google-spanner/setup.py
index 228cfd22bee5..e5c88ef94c02 100644
--- a/packages/django-google-spanner/setup.py
+++ b/packages/django-google-spanner/setup.py
@@ -71,6 +71,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
         "Topic :: Utilities",
         "Framework :: Django",
         "Framework :: Django :: 5.2",
diff --git a/packages/google-api-core/pyproject.toml b/packages/google-api-core/pyproject.toml
index 9bff8ce994cb..b281b6b5d66e 100644
--- a/packages/google-api-core/pyproject.toml
+++ b/packages/google-api-core/pyproject.toml
@@ -39,6 +39,7 @@ classifiers = [
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
   "Programming Language :: Python :: 3.14",
+  "Programming Language :: Python :: 3.15",
   "Operating System :: OS Independent",
   "Topic :: Internet",
 ]
diff --git a/packages/google-auth-httplib2/setup.py b/packages/google-auth-httplib2/setup.py
index c74a0f2f8012..ffda4ad44be7 100644
--- a/packages/google-auth-httplib2/setup.py
+++ b/packages/google-auth-httplib2/setup.py
@@ -47,6 +47,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
         "Development Status :: 3 - Alpha",
         "Intended Audience :: Developers",
         "License :: OSI Approved :: Apache Software License",
diff --git a/packages/google-auth-oauthlib/setup.py b/packages/google-auth-oauthlib/setup.py
index 11b9fba61512..a619e210f086 100644
--- a/packages/google-auth-oauthlib/setup.py
+++ b/packages/google-auth-oauthlib/setup.py
@@ -64,6 +64,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
         "Development Status :: 5 - Production/Stable",
         "Intended Audience :: Developers",
         "License :: OSI Approved :: Apache Software License",
diff --git a/packages/google-auth/setup.py b/packages/google-auth/setup.py
index 8807e7eb342b..64379d666a59 100644
--- a/packages/google-auth/setup.py
+++ b/packages/google-auth/setup.py
@@ -121,6 +121,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
         "Development Status :: 5 - Production/Stable",
         "Intended Audience :: Developers",
         "License :: OSI Approved :: Apache Software License",
diff --git a/packages/google-cloud-bigtable/noxfile.py b/packages/google-cloud-bigtable/noxfile.py
index fb5a3cab9c4b..07d5f5bc4c15 100644
--- a/packages/google-cloud-bigtable/noxfile.py
+++ b/packages/google-cloud-bigtable/noxfile.py
@@ -249,11 +249,6 @@ def install_unittest_dependencies(session, *constraints):
 def unit(session, protobuf_implementation):
     # Install all test dependencies, then install this package in-place.
 
-    # TODO(https://github.com/googleapis/google-cloud-python/issues/17741):
-    # Remove once `google-crc32c` wheels are published for 3.15
-    if session.python == "3.15":
-        session.skip("Skipping 3.15 until wheels are available for google-crc32c.")
-
     constraints_path = str(
         CURRENT_DIRECTORY / "testing" / f"constraints-{session.python}.txt"
     )
diff --git a/packages/google-cloud-core/setup.py b/packages/google-cloud-core/setup.py
index 4d28bc82c212..5b85859683d3 100644
--- a/packages/google-cloud-core/setup.py
+++ b/packages/google-cloud-core/setup.py
@@ -80,6 +80,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
         "Operating System :: OS Independent",
         "Topic :: Internet",
     ],
diff --git a/packages/google-cloud-dns/setup.py b/packages/google-cloud-dns/setup.py
index 21f64e31a38d..254ce81fb844 100644
--- a/packages/google-cloud-dns/setup.py
+++ b/packages/google-cloud-dns/setup.py
@@ -81,6 +81,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
         "Operating System :: OS Independent",
         "Topic :: Internet",
     ],
diff --git a/packages/google-cloud-documentai-toolbox/setup.py b/packages/google-cloud-documentai-toolbox/setup.py
index 8765caa5b94a..5842ac56fbcf 100644
--- a/packages/google-cloud-documentai-toolbox/setup.py
+++ b/packages/google-cloud-documentai-toolbox/setup.py
@@ -58,7 +58,8 @@
         "pandas[performance,gcp]>=2.0.0, <3.0.0; python_version < '3.15'",
         # pandas[performance] requires numba which does not have 3.15 support yet
         "pandas[gcp]>=2.0.0, <3.0.0;python_version>='3.15'",
-        "pyarrow>=15.0.0, <23.0.0",
+        # pyarrow is transitive dependency; not accessed by the library directly
+        "pyarrow>=15.0.0",
         "tabulate>=0.9.0, <1.0.0",
         "proto-plus>=1.26.1, <2.0.0",
         "grpc-google-iam-v1>=0.14.2, <1.0.0",
diff --git a/packages/google-cloud-ndb/setup.py b/packages/google-cloud-ndb/setup.py
index 4f886d22596b..cb442195107c 100644
--- a/packages/google-cloud-ndb/setup.py
+++ b/packages/google-cloud-ndb/setup.py
@@ -73,6 +73,7 @@ def main():
             "Programming Language :: Python :: 3.12",
             "Programming Language :: Python :: 3.13",
             "Programming Language :: Python :: 3.14",
+            "Programming Language :: Python :: 3.15",
             "Operating System :: OS Independent",
             "Topic :: Internet",
         ],
diff --git a/packages/google-cloud-runtimeconfig/setup.py b/packages/google-cloud-runtimeconfig/setup.py
index 8fb17e8cd5a0..b46ef501aae0 100644
--- a/packages/google-cloud-runtimeconfig/setup.py
+++ b/packages/google-cloud-runtimeconfig/setup.py
@@ -78,6 +78,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
         "Operating System :: OS Independent",
         "Topic :: Internet",
     ],
diff --git a/packages/google-cloud-spanner-dbapi-driver/setup.py b/packages/google-cloud-spanner-dbapi-driver/setup.py
index cfc0b06a229b..1761fca917ba 100644
--- a/packages/google-cloud-spanner-dbapi-driver/setup.py
+++ b/packages/google-cloud-spanner-dbapi-driver/setup.py
@@ -70,6 +70,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
         "Operating System :: OS Independent",
         "Topic :: Database",
     ],
diff --git a/packages/google-cloud-testutils/setup.py b/packages/google-cloud-testutils/setup.py
index c11ccac6c4f2..0512da2d4a9a 100644
--- a/packages/google-cloud-testutils/setup.py
+++ b/packages/google-cloud-testutils/setup.py
@@ -71,6 +71,7 @@
         "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: 3.13",
         "Programming Language :: Python :: 3.14",
+        "Programming Language :: Python :: 3.15",
         "Topic :: Internet",
         "Topic :: Software Development :: Libraries :: Python Modules",
     ],
diff --git a/packages/google-resumable-media/setup.py b/packages/google-resumable-media/setup.py
index a4b25e5b90e1..d7a21f741401 100644
--- a/packages/google-resumable-media/setup.py
+++ b/packages/google-resumable-media/setup.py
@@ -63,6 +63,7 @@
         'Programming Language :: Python :: 3.12',
         'Programming Language :: Python :: 3.13',
         'Programming Language :: Python :: 3.14',
+        'Programming Language :: Python :: 3.15',
         'Topic :: Internet',
     ],
 )
diff --git a/packages/proto-plus/pyproject.toml b/packages/proto-plus/pyproject.toml
index 4f0c30439ba1..553962d09191 100644
--- a/packages/proto-plus/pyproject.toml
+++ b/packages/proto-plus/pyproject.toml
@@ -34,6 +34,7 @@ classifiers = [
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
   "Programming Language :: Python :: 3.14",
+  "Programming Language :: Python :: 3.15",
   "Operating System :: OS Independent",
   "Topic :: Software Development :: Code Generators",
   "Topic :: Software Development :: Libraries :: Python Modules",