diff --git a/pytest_httpserver/httpserver.py b/pytest_httpserver/httpserver.py
index 20cdaf4..ba3f06f 100644
--- a/pytest_httpserver/httpserver.py
+++ b/pytest_httpserver/httpserver.py
@@ -982,10 +982,13 @@ def __init__(
         self._readiness_check_pending = False
 
     def start(self) -> None:
-        self._readiness_check_pending = self.startup_timeout is not None
-
         super().start()
-        self.wait_for_server_ready()
+        self._readiness_check_pending = self.startup_timeout is not None
+        try:
+            self.wait_for_server_ready()
+        except Exception:
+            self.stop()
+            raise
 
     def wait_for_server_ready(self) -> None:
         """
diff --git a/tests/test_readiness.py b/tests/test_readiness.py
index 2ddd025..2cb1ab2 100644
--- a/tests/test_readiness.py
+++ b/tests/test_readiness.py
@@ -1,9 +1,11 @@
 from collections.abc import Generator
+from typing import Any
 
 import pytest
 import requests
 
 from pytest_httpserver.httpserver import HTTPServer
+from pytest_httpserver.httpserver import HTTPServerError
 
 
 @pytest.fixture
@@ -22,3 +24,101 @@ def test_httpserver_readiness(httpserver: HTTPServer):
     resp = requests.get(httpserver.url_for("/"))
     assert resp.status_code == 200
     assert resp.text == "Hello, world!"
+
+
+class RecordingHTTPServer(HTTPServer):
+    """HTTPServer subclass that records wait_for_server_ready() calls."""
+
+    def __init__(self, **kwargs: Any) -> None:
+        super().__init__(**kwargs)
+        self.wait_for_ready_call_count = 0
+        self.readiness_pending_before_wait: list[bool] = []
+        self.readiness_pending_after_wait: list[bool] = []
+
+    def wait_for_server_ready(self) -> None:
+        self.wait_for_ready_call_count += 1
+        self.readiness_pending_before_wait.append(self._readiness_check_pending)
+        super().wait_for_server_ready()
+        self.readiness_pending_after_wait.append(self._readiness_check_pending)
+
+
+@pytest.fixture
+def recording_server_with_timeout() -> Generator[RecordingHTTPServer]:
+    with RecordingHTTPServer(startup_timeout=10) as server:
+        yield server
+
+
+@pytest.fixture
+def recording_server_without_timeout() -> Generator[RecordingHTTPServer]:
+    with RecordingHTTPServer() as server:
+        yield server
+
+
+def test_wait_for_server_ready_called_with_timeout(
+    recording_server_with_timeout: RecordingHTTPServer,
+) -> None:
+    assert recording_server_with_timeout.wait_for_ready_call_count == 1
+    assert recording_server_with_timeout.readiness_pending_before_wait == [True]
+    assert recording_server_with_timeout.readiness_pending_after_wait == [False]
+
+
+def test_wait_for_server_ready_called_without_timeout(
+    recording_server_without_timeout: RecordingHTTPServer,
+) -> None:
+    assert recording_server_without_timeout.wait_for_ready_call_count == 1
+    assert recording_server_without_timeout.readiness_pending_before_wait == [False]
+    assert recording_server_without_timeout.readiness_pending_after_wait == [False]
+
+
+def test_wait_for_server_ready_called_each_start_stop_cycle() -> None:
+    server = RecordingHTTPServer(startup_timeout=5)
+    try:
+        for i in range(3):
+            server.start()
+            assert server.wait_for_ready_call_count == i + 1
+            server.clear()
+            server.stop()
+    finally:
+        if server.is_running():
+            server.clear()
+            server.stop()
+
+    assert server.readiness_pending_before_wait == [True, True, True]
+    assert server.readiness_pending_after_wait == [False, False, False]
+
+
+def test_double_start_does_not_poison_readiness_flag() -> None:
+    server = HTTPServer(startup_timeout=5)
+    server.start()
+    try:
+        with pytest.raises(HTTPServerError, match="already running"):
+            server.start()
+
+        assert server._readiness_check_pending is False  # noqa: SLF001
+
+        server.expect_request("/test").respond_with_data("normal response")
+        resp = requests.get(server.url_for("/test"))
+        assert resp.status_code == 200
+        assert resp.text == "normal response"
+    finally:
+        server.clear()
+        if server.is_running():
+            server.stop()
+
+
+class FailingReadinessServer(HTTPServer):
+    """HTTPServer subclass whose readiness check always fails."""
+
+    def __init__(self, **kwargs: Any) -> None:
+        super().__init__(**kwargs)
+
+    def wait_for_server_ready(self) -> None:
+        raise HTTPServerError("Simulated readiness failure")
+
+
+def test_readiness_failure_stops_server() -> None:
+    server = FailingReadinessServer(startup_timeout=5)
+    with pytest.raises(HTTPServerError, match="Simulated readiness failure"):
+        server.start()
+
+    assert not server.is_running()