diff --git a/src/cmd/go/go_test.go b/src/cmd/go/go_test.go
index 37da67c8b7..e6eec09082 100644
--- a/src/cmd/go/go_test.go
+++ b/src/cmd/go/go_test.go
@@ -99,6 +99,7 @@ func TestMain(m *testing.M) {
 	// Don't let these environment variables confuse the test.
 	os.Unsetenv("GOBIN")
 	os.Unsetenv("GOPATH")
+	os.Unsetenv("GIT_ALLOW_PROTOCOL")
 	if home, ccacheDir := os.Getenv("HOME"), os.Getenv("CCACHE_DIR"); home != "" && ccacheDir == "" {
 		// On some systems the default C compiler is ccache.
 		// Setting HOME to a non-existent directory will break
diff --git a/src/cmd/go/vcs_test.go b/src/cmd/go/vcs_test.go
index 798f6683a6..c73f5d0e85 100644
--- a/src/cmd/go/vcs_test.go
+++ b/src/cmd/go/vcs_test.go
@@ -271,6 +271,7 @@ func TestIsSecureGitAllowProtocol(t *testing.T) {
 		{vcsBzr, "foo://example.com/bar.bzr", false},
 	}
 
+	defer os.Unsetenv("GIT_ALLOW_PROTOCOL")
 	os.Setenv("GIT_ALLOW_PROTOCOL", "https:foo")
 	for _, test := range tests {
 		secure := test.vcs.isSecure(test.url)