diff --git a/src/pkg/os/exec/lp_plan9.go b/src/pkg/os/exec/lp_plan9.go
index 6846a35c85f..5aa8a54ed81 100644
--- a/src/pkg/os/exec/lp_plan9.go
+++ b/src/pkg/os/exec/lp_plan9.go
@@ -28,6 +28,7 @@ func findExecutable(file string) error {
 // in the directories named by the path environment variable.
 // If file begins with "/", "#", "./", or "../", it is tried
 // directly and the path is not consulted.
+// The result may be an absolute path or a path relative to the current directory.
 func LookPath(file string) (string, error) {
 	// skip the path lookup for these prefixes
 	skip := []string{"/", "#", "./", "../"}
diff --git a/src/pkg/os/exec/lp_unix.go b/src/pkg/os/exec/lp_unix.go
index 1d1ec07da4d..7aee50cb788 100644
--- a/src/pkg/os/exec/lp_unix.go
+++ b/src/pkg/os/exec/lp_unix.go
@@ -29,6 +29,7 @@ func findExecutable(file string) error {
 // LookPath searches for an executable binary named file
 // in the directories named by the PATH environment variable.
 // If file contains a slash, it is tried directly and the PATH is not consulted.
+// The result may be an absolute path or a path relative to the current directory.
 func LookPath(file string) (string, error) {
 	// NOTE(rsc): I wish we could use the Plan 9 behavior here
 	// (only bypass the path if file begins with / or ./ or ../)
diff --git a/src/pkg/os/exec/lp_windows.go b/src/pkg/os/exec/lp_windows.go
index 7c7289bceea..7ec4c740434 100644
--- a/src/pkg/os/exec/lp_windows.go
+++ b/src/pkg/os/exec/lp_windows.go
@@ -47,6 +47,7 @@ func findExecutable(file string, exts []string) (string, error) {
 // If file contains a slash, it is tried directly and the PATH is not consulted.
 // LookPath also uses PATHEXT environment variable to match
 // a suitable candidate.
+// The result may be an absolute path or a path relative to the current directory.
 func LookPath(file string) (f string, err error) {
 	x := os.Getenv(`PATHEXT`)
 	if x == `` {