diff --git a/archive/changes_unix.go b/archive/changes_unix.go
index a2ccbb2..05f109a 100644
--- a/archive/changes_unix.go
+++ b/archive/changes_unix.go
@@ -12,7 +12,7 @@ func statDifferent(oldStat *system.StatT, newStat *system.StatT) bool {
 	// Don't look at size for dirs, its not a good measure of change
 	if oldStat.Mode() != newStat.Mode() ||
 		oldStat.UID() != newStat.UID() ||
-		oldStat.Gid() != newStat.Gid() ||
+		oldStat.GID() != newStat.GID() ||
 		oldStat.Rdev() != newStat.Rdev() ||
 		// Don't look at size for dirs, its not a good measure of change
 		(oldStat.Mode()&syscall.S_IFDIR != syscall.S_IFDIR &&
diff --git a/system/stat.go b/system/stat.go
index 7392c82..087034c 100644
--- a/system/stat.go
+++ b/system/stat.go
@@ -27,8 +27,8 @@ func (s StatT) UID() uint32 {
 	return s.uid
 }
 
-// Gid returns file's group id of owner.
-func (s StatT) Gid() uint32 {
+// GID returns file's group id of owner.
+func (s StatT) GID() uint32 {
 	return s.gid
 }
 
diff --git a/system/stat_unix_test.go b/system/stat_unix_test.go
index 8b3c42b..dee8d30 100644
--- a/system/stat_unix_test.go
+++ b/system/stat_unix_test.go
@@ -27,7 +27,7 @@ func TestFromStatT(t *testing.T) {
 	if stat.Uid != s.UID() {
 		t.Fatal("got invalid uid")
 	}
-	if stat.Gid != s.Gid() {
+	if stat.Gid != s.GID() {
 		t.Fatal("got invalid gid")
 	}
 	if stat.Rdev != s.Rdev() {