diff --git a/cmd/guru/guru_test.go b/cmd/guru/guru_test.go
index b4073d94..62dcd6d3 100644
--- a/cmd/guru/guru_test.go
+++ b/cmd/guru/guru_test.go
@@ -242,6 +242,12 @@ func TestGuru(t *testing.T) {
 		"testdata/src/referrers-json/main.go",
 		"testdata/src/what-json/main.go",
 	} {
+		if filename == "testdata/src/referrers/main.go" && runtime.GOOS == "plan9" {
+			// Disable this test on plan9 since it expects a particular
+			// wording for a "no such file or directory" error.
+			continue
+		}
+
 		json := strings.Contains(filename, "-json/")
 		queries := parseQueries(t, filename)
 		golden := filename + "lden"
diff --git a/oracle/oracle_test.go b/oracle/oracle_test.go
index 0dd1cdcd..4aec489c 100644
--- a/oracle/oracle_test.go
+++ b/oracle/oracle_test.go
@@ -228,6 +228,12 @@ func TestOracle(t *testing.T) {
 		"testdata/src/referrers-json/main.go",
 		"testdata/src/what-json/main.go",
 	} {
+		if filename == "testdata/src/referrers/main.go" && runtime.GOOS == "plan9" {
+			// Disable this test on plan9 since it expects a particular
+			// wording for a "no such file or directory" error.
+			continue
+		}
+
 		useJson := strings.Contains(filename, "-json/")
 		queries := parseQueries(t, filename)
 		golden := filename + "lden"