diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index ddda393f47..cc2f3cf8d8 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -813,6 +813,10 @@
 // 	    Install packages that are dependencies of the test.
 // 	    Do not run the test.
 //
+// 	-json
+// 	    Convert test output to JSON suitable for automated processing.
+// 	    See 'go doc test2json' for the encoding details.
+//
 // 	-o file
 // 	    Compile the test binary to the named file.
 // 	    The test still runs (unless -c or -i is specified).
diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index 0a0f149e7d..15c43581e6 100644
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -143,6 +143,10 @@ In addition to the build flags, the flags handled by 'go test' itself are:
 	    Install packages that are dependencies of the test.
 	    Do not run the test.
 
+	-json
+	    Convert test output to JSON suitable for automated processing.
+	    See 'go doc test2json' for the encoding details.
+
 	-o file
 	    Compile the test binary to the named file.
 	    The test still runs (unless -c or -i is specified).