diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index f227d93de7..3a4473902c 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -2264,6 +2264,7 @@
 // The go command caches build outputs for reuse in future builds.
 // The default location for cache data is a subdirectory named go-build
 // in the standard user cache directory for the current operating system.
+// The cache is safe for concurrent invocations of the go command.
 // Setting the GOCACHE environment variable overrides this default,
 // and running 'go env GOCACHE' prints the current cache directory.
 //
diff --git a/src/cmd/go/internal/help/helpdoc.go b/src/cmd/go/internal/help/helpdoc.go
index d373c675f6..e1240de710 100644
--- a/src/cmd/go/internal/help/helpdoc.go
+++ b/src/cmd/go/internal/help/helpdoc.go
@@ -809,6 +809,7 @@ var HelpCache = &base.Command{
 The go command caches build outputs for reuse in future builds.
 The default location for cache data is a subdirectory named go-build
 in the standard user cache directory for the current operating system.
+The cache is safe for concurrent invocations of the go command.
 Setting the GOCACHE environment variable overrides this default,
 and running 'go env GOCACHE' prints the current cache directory.