diff --git a/run_cross_test.py b/run_cross_test.py
index 71914028f..2b640ec86 100755
--- a/run_cross_test.py
+++ b/run_cross_test.py
@@ -38,7 +38,7 @@ def runtests(cross_file):
     print('\nTotal passed cross tests:', passing_tests)
     print('Total failed cross tests:', failing_tests)
     print('Total skipped cross tests:', skipped_tests)
-    if failing_tests > 0 and ('TRAVIS' in os.environ or 'APPVEYOR' in os.environ):
+    if failing_tests > 0 and ('CI' in os.environ):
         print('\nMesonlogs of failing tests\n')
         for l in failing_logs:
             print(l, '\n')
diff --git a/run_project_tests.py b/run_project_tests.py
index 876d1359a..a9c7eca7a 100755
--- a/run_project_tests.py
+++ b/run_project_tests.py
@@ -81,7 +81,7 @@ class AutoDeletedDir:
 
 failing_logs = []
 print_debug = 'MESON_PRINT_TEST_OUTPUT' in os.environ
-under_ci = not {'TRAVIS', 'APPVEYOR'}.isdisjoint(os.environ)
+under_ci = 'CI' in os.environ
 do_debug = under_ci or print_debug
 no_meson_log_msg = 'No meson-log.txt found.'
 
diff --git a/run_tests.py b/run_tests.py
index af926eab3..242338825 100755
--- a/run_tests.py
+++ b/run_tests.py
@@ -245,7 +245,7 @@ if __name__ == '__main__':
             elif arg == '--cross=arm':
                 cross = 'arm'
     # Running on a developer machine? Be nice!
-    if not mesonlib.is_windows() and not mesonlib.is_haiku() and 'TRAVIS' not in os.environ:
+    if not mesonlib.is_windows() and not mesonlib.is_haiku() and 'CI' not in os.environ:
         os.nice(20)
     # Appveyor sets the `platform` environment variable which completely messes
     # up building with the vs2010 and vs2015 backends.
diff --git a/run_unittests.py b/run_unittests.py
index 9ffce52f4..e02bc6c51 100755
--- a/run_unittests.py
+++ b/run_unittests.py
@@ -81,7 +81,7 @@ def is_tarball():
     return False
 
 def is_ci():
-    if 'TRAVIS' in os.environ or 'APPVEYOR' in os.environ:
+    if 'CI' in os.environ:
         return True
     return False
 
@@ -98,8 +98,8 @@ def _git_init(project_dir):
 
 def skipIfNoPkgconfig(f):
     '''
-    Skip this test if no pkg-config is found, unless we're on Travis or
-    Appveyor CI.  This allows users to run our test suite without having
+    Skip this test if no pkg-config is found, unless we're on CI.
+    This allows users to run our test suite without having
     pkg-config installed on, f.ex., macOS, while ensuring that our CI does not
     silently skip the test because of misconfiguration.
 
@@ -1671,7 +1671,7 @@ class AllPlatformTests(BasePlatformTests):
                 self.assertIsInstance(linker, lib)
                 self.assertEqual(cc.id, 'msvc')
                 self.assertTrue(hasattr(cc, 'is_64'))
-                # If we're in the appveyor CI, we know what the compiler will be
+                # If we're on Windows CI, we know what the compiler will be
                 if 'arch' in os.environ:
                     if os.environ['arch'] == 'x64':
                         self.assertTrue(cc.is_64)
diff --git a/test cases/frameworks/17 mpi/meson.build b/test cases/frameworks/17 mpi/meson.build
index 1085d40c8..b2f9fb853 100644
--- a/test cases/frameworks/17 mpi/meson.build	
+++ b/test cases/frameworks/17 mpi/meson.build	
@@ -17,7 +17,7 @@ exec = executable('exec',
 test('MPI C', exec)
 
 if build_machine.system() != 'windows'
-  # C++ MPI not supported by MS-MPI used on AppVeyor.
+  # C++ MPI not supported by MS-MPI
   mpicpp = dependency('mpi', language : 'cpp')
   execpp = executable('execpp',
     'main.cpp',