diff --git a/cmd/godoc/x.go b/cmd/godoc/x.go
index e6e2e1e155..0815152d72 100644
--- a/cmd/godoc/x.go
+++ b/cmd/godoc/x.go
@@ -33,6 +33,7 @@ var xMap = map[string]xRepo{
 	"mobile":     {"https://go.googlesource.com/mobile", "git"},
 	"net":        {"https://go.googlesource.com/net", "git"},
 	"oauth2":     {"https://go.googlesource.com/oauth2", "git"},
+	"playground": {"https://go.googlesource.com/playground", "git"},
 	"review":     {"https://go.googlesource.com/review", "git"},
 	"sys":        {"https://go.googlesource.com/sys", "git"},
 	"talks":      {"https://go.googlesource.com/talks", "git"},