diff --git a/gio/tests/meson.build b/gio/tests/meson.build
index 01acf0a95..ce71ad308 100644
--- a/gio/tests/meson.build
+++ b/gio/tests/meson.build
@@ -1116,7 +1116,7 @@ foreach test_name, extra_args : gio_tests
     if installed_tests_env != {}
       envs = []
       foreach var, value : installed_tests_env
-         envs += '@0@=@1@'.format(var, value)
+        envs += '@0@=\'@1@\''.format(var, value)
       endforeach
       test_env_override = '@0@ @1@ '.format(env_program.full_path(), ' '.join(envs))
     endif
diff --git a/girepository/tests/meson.build b/girepository/tests/meson.build
index d3c7ea05a..313d09b2f 100644
--- a/girepository/tests/meson.build
+++ b/girepository/tests/meson.build
@@ -107,7 +107,7 @@ foreach test_name, extra_args : girepository_tests
     if installed_tests_env != {}
       envs = []
       foreach var, value : installed_tests_env
-         envs += '@0@=@1@'.format(var, value)
+        envs += '@0@=\'@1@\''.format(var, value)
       endforeach
       test_env_override = '@0@ @1@ '.format(env_program.full_path(), ' '.join(envs))
     endif
diff --git a/glib/tests/meson.build b/glib/tests/meson.build
index e0c077505..0b1f70a91 100644
--- a/glib/tests/meson.build
+++ b/glib/tests/meson.build
@@ -434,7 +434,7 @@ foreach test_name, extra_args : glib_tests
     if installed_tests_env != {}
       envs = []
       foreach var, value : installed_tests_env
-         envs += '@0@=@1@'.format(var, value)
+        envs += '@0@=\'@1@\''.format(var, value)
       endforeach
       test_env_override = '@0@ @1@ '.format(env_program.full_path(), ' '.join(envs))
     endif