diff --git a/.librarian/generator-input/client-post-processing/bigtable-integration.yaml b/.librarian/generator-input/client-post-processing/bigtable-integration.yaml
index 09593bdefc30..2953a7f52135 100644
--- a/.librarian/generator-input/client-post-processing/bigtable-integration.yaml
+++ b/.librarian/generator-input/client-post-processing/bigtable-integration.yaml
@@ -417,7 +417,7 @@ replacements:
           "google-cloud-testutils",
       ]
       SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = [
-          "pytest-asyncio==0.21.2",
+          "pytest-asyncio>=0.26.0",
           "pytest-order==1.3.0",
           RUFF_VERSION,
           "pyyaml==6.0.2",
diff --git a/packages/google-cloud-bigtable/noxfile.py b/packages/google-cloud-bigtable/noxfile.py
index 8f68486cd3a3..88d0237720fa 100644
--- a/packages/google-cloud-bigtable/noxfile.py
+++ b/packages/google-cloud-bigtable/noxfile.py
@@ -57,7 +57,7 @@
     "google-cloud-testutils",
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = [
-    "pytest-asyncio==0.21.2",
+    "pytest-asyncio>=0.26.0",
     "pytest-order==1.3.0",
     RUFF_VERSION,
     "pyyaml==6.0.2",
diff --git a/packages/google-cloud-bigtable/tests/system/conftest.py b/packages/google-cloud-bigtable/tests/system/conftest.py
index e9cb2fcc91e8..7a7b315ec542 100644
--- a/packages/google-cloud-bigtable/tests/system/conftest.py
+++ b/packages/google-cloud-bigtable/tests/system/conftest.py
@@ -15,19 +15,8 @@
 Import pytest fixtures for setting up table for data client system tests
 """
 
-import asyncio
 import os
 import sys
 
-import pytest
-
 script_path = os.path.dirname(os.path.realpath(__file__))
 sys.path.append(script_path)
-
-
-@pytest.fixture(scope="session")
-def event_loop():
-    loop = asyncio.new_event_loop()
-    yield loop
-    loop.stop()
-    loop.close()
diff --git a/packages/google-cloud-bigtable/tests/system/pytest.ini b/packages/google-cloud-bigtable/tests/system/pytest.ini
new file mode 100644
index 000000000000..ae7833d23bf6
--- /dev/null
+++ b/packages/google-cloud-bigtable/tests/system/pytest.ini
@@ -0,0 +1,8 @@
+[pytest]
+# The data client system tests share a single client across the whole session
+# (see the session-scoped `client`/`target`/`table` fixtures), so every async
+# fixture and test must run on the same event loop. Run them all on a single
+# session-scoped loop, matching the previous session-scoped `event_loop`
+# override that pytest-asyncio removed in 1.0.
+asyncio_default_test_loop_scope = session
+asyncio_default_fixture_loop_scope = session