diff --git a/poetry.lock b/poetry.lock
index 08dbfd5f..9215b275 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -40,6 +40,21 @@ files = [
     {file = "backports_asyncio_runner-1.2.0.tar.gz", hash = "sha256:a5aa7b2b7d8f8bfcaa2b57313f70792df84e32a2a746f585213373f900b42162"},
 ]
 
+[[package]]
+name = "blockbuster"
+version = "1.5.26"
+description = "Utility to detect blocking calls in the async event loop"
+optional = false
+python-versions = ">=3.8"
+groups = ["dev"]
+files = [
+    {file = "blockbuster-1.5.26-py3-none-any.whl", hash = "sha256:f8e53fb2dd4b6c6ec2f04907ddbd063ca7cd1ef587d24448ef4e50e81e3a79bb"},
+    {file = "blockbuster-1.5.26.tar.gz", hash = "sha256:cc3ce8c70fa852a97ee3411155f31e4ad2665cd1c6c7d2f8bb1851dab61dc629"},
+]
+
+[package.dependencies]
+forbiddenfruit = {version = ">=0.1.4", markers = "implementation_name == \"cpython\""}
+
 [[package]]
 name = "certifi"
 version = "2025.1.31"
@@ -348,6 +363,18 @@ files = [
 [package.extras]
 test = ["pytest (>=6)"]
 
+[[package]]
+name = "forbiddenfruit"
+version = "0.1.4"
+description = "Patch python built-in objects"
+optional = false
+python-versions = "*"
+groups = ["dev"]
+markers = "implementation_name == \"cpython\""
+files = [
+    {file = "forbiddenfruit-0.1.4.tar.gz", hash = "sha256:e3f7e66561a29ae129aac139a85d610dbf3dd896128187ed5454b6421f624253"},
+]
+
 [[package]]
 name = "idna"
 version = "3.15"
@@ -1003,7 +1030,7 @@ version = "2.7.0"
 description = "HTTP library with thread-safe connection pooling, file post, and more."
 optional = false
 python-versions = ">=3.10"
-groups = ["dev", "docs"]
+groups = ["docs"]
 files = [
     {file = "urllib3-2.7.0-py3-none-any.whl", hash = "sha256:9fb4c81ebbb1ce9531cce37674bbc6f1360472bc18ca9a553ede278ef7276897"},
     {file = "urllib3-2.7.0.tar.gz", hash = "sha256:231e0ec3b63ceb14667c67be60f2f2c40a518cb38b03af60abc813da26505f4c"},
@@ -1018,4 +1045,4 @@ zstd = ["backports-zstd (>=1.0.0) ; python_version < \"3.14\""]
 [metadata]
 lock-version = "2.1"
 python-versions = "^3.10"
-content-hash = "d5c5962b015fd229695b0a8024a848e7f11878a3efc36cb9a48c2279f48a9777"
+content-hash = "c0d62f11cb94761d233c73a46ff3f626640ae3ef3af9a2ece9f37095a47d4c71"
diff --git a/pyproject.toml b/pyproject.toml
index b63728c6..94e4a08f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -91,6 +91,7 @@ cython = "^3.2.4"
 setuptools = ">=65.6.3,<83.0.0"
 pytest-timeout = "^2.1.0"
 pytest-codspeed = ">=5.0.2,<6.0"
+blockbuster = ">=1.5.5,<2.0.0"
 
 [tool.poetry.group.docs.dependencies]
 sphinx = "^7.4.7 || ^8.1.3"
diff --git a/tests/conftest.py b/tests/conftest.py
index 1a76efe9..573b9394 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -3,7 +3,7 @@
 from __future__ import annotations
 
 import threading
-from collections.abc import AsyncGenerator, Generator
+from collections.abc import AsyncGenerator, Generator, Iterator
 from unittest.mock import patch
 
 import pytest
@@ -15,6 +15,64 @@
 from zeroconf._services import info as service_info
 from zeroconf.asyncio import AsyncZeroconf
 
+try:
+    from blockbuster import BlockBuster, blockbuster_ctx
+except ImportError:  # platforms without blockbuster (e.g. PyPy under QEMU)
+    BlockBuster = None  # type: ignore[assignment,misc]
+    blockbuster_ctx = None  # type: ignore[assignment]
+
+_BENCHMARKS_DIR = "tests/benchmarks"
+
+# Tests that perform sync IO inside the asyncio event loop and trip
+# blockbuster. Marked xfail (strict=False) so CI stays green; pop
+# entries as the underlying blocking calls get fixed. Most of the
+# `test_async_service_registration*` and `test_async_tasks` entries
+# share a single root cause: `Zeroconf.async_close()` -> ... ->
+# `ServiceBrowser.cancel()` calls `Thread.join()` to drain the
+# dedicated browser thread, and on Python 3.10-3.12 the thread is
+# still alive when the join happens. `test_use_asyncio_false_*` is
+# by design (sync bootstrap when `use_asyncio=False` is requested from
+# inside a running loop); `test_run_coro_with_timeout` exercises the
+# sync-from-thread bridge intentionally. The strict=False marker keeps
+# the suite green on the Python versions where the race resolves the
+# other way.
+_KNOWN_BLOCKING: frozenset[str] = frozenset(
+    {
+        "tests/test_asyncio.py::test_async_service_registration",
+        "tests/test_asyncio.py::test_async_service_registration_with_server_missing",
+        "tests/test_asyncio.py::test_async_service_registration_same_server_different_ports",
+        "tests/test_asyncio.py::test_async_service_registration_same_server_same_ports",
+        "tests/test_asyncio.py::test_async_tasks",
+        "tests/test_core.py::Framework::test_use_asyncio_false_forces_thread_when_loop_running",
+        "tests/utils/test_asyncio.py::test_run_coro_with_timeout",
+    }
+)
+
+
+def pytest_collection_modifyitems(config: pytest.Config, items: list[pytest.Item]) -> None:
+    """Mark known-blocking tests xfail so blockbuster doesn't fail the suite."""
+    if blockbuster_ctx is None:
+        return
+    marker = pytest.mark.xfail(
+        reason="blockbuster: blocking call in asyncio path",
+        strict=False,
+    )
+    for item in items:
+        if item.nodeid in _KNOWN_BLOCKING:
+            item.add_marker(marker)
+
+
+@pytest.fixture(autouse=True)
+def blockbuster(
+    request: pytest.FixtureRequest,
+) -> Iterator[BlockBuster | None]:
+    """Fail any test that performs a blocking call inside the asyncio loop."""
+    if blockbuster_ctx is None or _BENCHMARKS_DIR in str(request.node.fspath):
+        yield None
+        return
+    with blockbuster_ctx() as bb:
+        yield bb
+
 
 @pytest.fixture(autouse=True)
 def verify_threads_ended():