diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
index 88f74c57b2ef..6b4182f326da 100644
--- a/lib/matplotlib/backend_bases.py
+++ b/lib/matplotlib/backend_bases.py
@@ -2316,7 +2316,7 @@ def start_event_loop(self, timeout=0):
         The event loop blocks until a callback function triggers
         `stop_event_loop`, or *timeout* is reached.
 
-        If *timeout* is negative, never timeout.
+        If *timeout* is 0 or negative, never timeout.
 
         Only interactive backends need to reimplement this method and it relies
         on `flush_events` being properly implemented.
diff --git a/lib/matplotlib/backends/backend_qt5.py b/lib/matplotlib/backends/backend_qt5.py
index 24f0c24fc02a..27c23435f87b 100644
--- a/lib/matplotlib/backends/backend_qt5.py
+++ b/lib/matplotlib/backends/backend_qt5.py
@@ -426,7 +426,7 @@ def start_event_loop(self, timeout=0):
         if hasattr(self, "_event_loop") and self._event_loop.isRunning():
             raise RuntimeError("Event loop already running")
         self._event_loop = event_loop = QtCore.QEventLoop()
-        if timeout:
+        if timeout > 0:
             timer = QtCore.QTimer.singleShot(timeout * 1000, event_loop.quit)
         event_loop.exec_()