diff --git a/tests/gl-shim.pl b/tests/gl-shim.pl
index 2c33983f2284e4deebb4e99a6e2ad8d35c52354f..3ff45e451da56eb0e2b519d0e716c921e939b75c 100755
--- a/tests/gl-shim.pl
+++ b/tests/gl-shim.pl
@@ -43,6 +43,7 @@ if (length $ENV{CAPSULE_TESTS_UNINSTALLED}) {
     # Make sure the shim can load the just-built libcapsule
     push @libcapsule_environment, "LD_LIBRARY_PATH=$ENV{G_TEST_BUILDDIR}/.libs";
 }
+delete $ENV{MAKEFLAGS};
 
 my $examples = "$srcdir/examples";
 
diff --git a/tests/init-project.pl b/tests/init-project.pl
index 9d4ad448af24b188f7cc4da6391f9f95a0dc512d..3bca8297ad2c5f185d9114eaedbae085530a6f7a 100755
--- a/tests/init-project.pl
+++ b/tests/init-project.pl
@@ -43,6 +43,7 @@ if (length $ENV{CAPSULE_TESTS_UNINSTALLED}) {
     # Make sure the shim can load the just-built libcapsule
     push @libcapsule_environment, "LD_LIBRARY_PATH=$ENV{G_TEST_BUILDDIR}/.libs";
 }
+delete $ENV{MAKEFLAGS};
 
 my @configure_arguments = ();