diff --git a/src/cmd/go/internal/modindex/syslist.go b/src/cmd/go/internal/modindex/syslist.go
index 69b8fac331e..41adcc5342d 100644
--- a/src/cmd/go/internal/modindex/syslist.go
+++ b/src/cmd/go/internal/modindex/syslist.go
@@ -25,6 +25,7 @@ var knownOS = map[string]bool{
 	"openbsd":   true,
 	"plan9":     true,
 	"solaris":   true,
+	"wasip1":    true,
 	"windows":   true,
 	"zos":       true,
 }