diff --git a/src/archive/tar/writer.go b/src/archive/tar/writer.go
index 059669767f2b9d..f966c5b4c648f5 100644
--- a/src/archive/tar/writer.go
+++ b/src/archive/tar/writer.go
@@ -424,6 +424,9 @@ func (tw *Writer) AddFS(fsys fs.FS) error {
 			return err
 		}
 		h.Name = name
+		if d.IsDir() {
+			h.Name += "/"
+		}
 		if err := tw.WriteHeader(h); err != nil {
 			return err
 		}
diff --git a/src/archive/tar/writer_test.go b/src/archive/tar/writer_test.go
index 2a01915d368c5a..7b10bf6a700d7f 100644
--- a/src/archive/tar/writer_test.go
+++ b/src/archive/tar/writer_test.go
@@ -1382,7 +1382,11 @@ func TestWriterAddFS(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		if hdr.Name != name {
+		tmpName := name
+		if entryInfo.IsDir() {
+			tmpName += "/"
+		}
+		if hdr.Name != tmpName {
 			t.Errorf("test fs has filename %v; archive header has %v",
 				name, hdr.Name)
 		}
diff --git a/src/archive/zip/writer.go b/src/archive/zip/writer.go
index cbe5ba262747f6..0a310054e37678 100644
--- a/src/archive/zip/writer.go
+++ b/src/archive/zip/writer.go
@@ -520,6 +520,9 @@ func (w *Writer) AddFS(fsys fs.FS) error {
 			return err
 		}
 		h.Name = name
+		if d.IsDir() {
+			h.Name += "/"
+		}
 		h.Method = Deflate
 		fw, err := w.CreateHeader(h)
 		if err != nil {
diff --git a/src/archive/zip/writer_test.go b/src/archive/zip/writer_test.go
index 27a99b6b3a13b9..44592ce8318826 100644
--- a/src/archive/zip/writer_test.go
+++ b/src/archive/zip/writer_test.go
@@ -633,7 +633,7 @@ func TestWriterAddFS(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	// Add subfolder into fsys to match what we'll read from the tar.
+	// Add subfolder into fsys to match what we'll read from the zip.
 	tests = append(tests[:2:2], WriteTest{Name: "subfolder", Mode: 0o555 | os.ModeDir}, tests[2])
 
 	// read it back
@@ -642,6 +642,9 @@ func TestWriterAddFS(t *testing.T) {
 		t.Fatal(err)
 	}
 	for i, wt := range tests {
+		if wt.Mode.IsDir() {
+			wt.Name += "/"
+		}
 		testReadFile(t, r.File[i], &wt)
 	}
 }