diff --git a/Lib/test/test_termios.py b/Lib/test/test_termios.py
index 84062e464d6caf..e7a3ba3eb8d6b7 100644
--- a/Lib/test/test_termios.py
+++ b/Lib/test/test_termios.py
@@ -194,6 +194,9 @@ def test_tcflow(self):
             termios.tcflow(self.fd, termios.TCOON)
             termios.tcflow(self.fd, termios.TCIOFF)
             termios.tcflow(self.fd, termios.TCION)
+            # Discard the transmitted STOP and START characters,
+            # otherwise closing the pseudo-terminal can block.
+            termios.tcflush(self.fd, termios.TCOFLUSH)
 
     @support.skip_android_selinux('tcflow')
     def test_tcflow_errors(self):