diff --git a/Lib/fontTools/ttLib/tables/S_V_G_.py b/Lib/fontTools/ttLib/tables/S_V_G_.py
index d49afdca0..49e98d034 100644
--- a/Lib/fontTools/ttLib/tables/S_V_G_.py
+++ b/Lib/fontTools/ttLib/tables/S_V_G_.py
@@ -110,7 +110,9 @@ class table_S_V_G_(DefaultTable.DefaultTable):
 			if (allCompressed or doc.compressed) and not docBytes.startswith(b"\x1f\x8b"):
 				import gzip
 				bytesIO = BytesIO()
-				with gzip.GzipFile(None, "w", fileobj=bytesIO) as gzipper:
+				# mtime=0 strips the useless timestamp and makes gzip output reproducible;
+				# equivalent to `gzip -n`
+				with gzip.GzipFile(None, "w", fileobj=bytesIO, mtime=0) as gzipper:
 					gzipper.write(docBytes)
 				gzipped = bytesIO.getvalue()
 				if len(gzipped) < len(docBytes):
diff --git a/Tests/ttLib/tables/S_V_G__test.py b/Tests/ttLib/tables/S_V_G__test.py
index 9a6e33e30..4c40556e2 100644
--- a/Tests/ttLib/tables/S_V_G__test.py
+++ b/Tests/ttLib/tables/S_V_G__test.py
@@ -16,7 +16,7 @@ def dump(table, ttFont=None):
 
 def compress(data: bytes) -> bytes:
     buf = io.BytesIO()
-    with gzip.GzipFile(None, "w", fileobj=buf) as gz:
+    with gzip.GzipFile(None, "w", fileobj=buf, mtime=0) as gz:
         gz.write(data)
     return buf.getvalue()