diff --git a/src/net/http/httputil/reverseproxy_test.go b/src/net/http/httputil/reverseproxy_test.go
index f089ce0574..a826dc82fe 100644
--- a/src/net/http/httputil/reverseproxy_test.go
+++ b/src/net/http/httputil/reverseproxy_test.go
@@ -23,6 +23,7 @@ import (
 	"net/url"
 	"os"
 	"reflect"
+	"runtime"
 	"slices"
 	"strconv"
 	"strings"
@@ -1560,6 +1561,11 @@ func TestReverseProxyWebSocketHalfTCP(t *testing.T) {
 	// - that closing the write stream is propagated through the proxy and results in reading
 	//   EOF at the other end of the connection
 
+	switch runtime.GOOS {
+	case "plan9":
+		t.Skipf("not supported on %s", runtime.GOOS)
+	}
+
 	mustRead := func(t *testing.T, conn *net.TCPConn, msg string) {
 		b := make([]byte, len(msg))
 		if _, err := conn.Read(b); err != nil {