diff --git a/test/test_ui.py b/test/test_ui.py
index 61e3ff33e..ab8cc289d 100644
--- a/test/test_ui.py
+++ b/test/test_ui.py
@@ -1123,12 +1123,18 @@ class CompletionTest(_common.TestCase, TestHelper):
         config['pluginpath'] = [_common.PLUGINPATH]
         config['plugins'] = ['test']
 
-        # Tests run in bash
+        # Do not load any other bash completion scripts on the system.
+        env = dict(os.environ)
+        env['BASH_COMPLETION_DIR'] = os.devnull
+        env['BASH_COMPLETION_COMPAT_DIR'] = os.devnull
+
+        # Open a `bash` process to run the tests in. We'll pipe in bash
+        # commands via stdin.
         cmd = os.environ.get('BEETS_TEST_SHELL', '/bin/bash --norc').split()
         if not has_program(cmd[0]):
             self.skipTest(u'bash not available')
         tester = subprocess.Popen(cmd, stdin=subprocess.PIPE,
-                                  stdout=subprocess.PIPE)
+                                  stdout=subprocess.PIPE, env=env)
 
         # Load bash_completion library.
         for path in commands.BASH_COMPLETION_PATHS: