diff --git a/src/cmd/go/alldocs.go b/src/cmd/go/alldocs.go
index 910699caced7e8..88f2e21f822d1a 100644
--- a/src/cmd/go/alldocs.go
+++ b/src/cmd/go/alldocs.go
@@ -2333,6 +2333,10 @@
 //	GOCACHE
 //		The directory where the go command will store cached
 //		information for reuse in future builds.
+//	GOCACHEPROG
+//		A command (with optional space-separated flags) that implements an
+//		external go command build cache.
+//		See 'go doc cmd/go/internal/cacheprog'.
 //	GODEBUG
 //		Enable various debugging facilities. See https://go.dev/doc/godebug
 //		for details.
diff --git a/src/cmd/go/internal/help/helpdoc.go b/src/cmd/go/internal/help/helpdoc.go
index 7e19ba93d2a83d..311584d4f0f1f3 100644
--- a/src/cmd/go/internal/help/helpdoc.go
+++ b/src/cmd/go/internal/help/helpdoc.go
@@ -506,6 +506,10 @@ General-purpose environment variables:
 	GOCACHE
 		The directory where the go command will store cached
 		information for reuse in future builds.
+	GOCACHEPROG
+		A command (with optional space-separated flags) that implements an
+		external go command build cache.
+		See 'go doc cmd/go/internal/cacheprog'.
 	GODEBUG
 		Enable various debugging facilities. See https://go.dev/doc/godebug
 		for details.