Y mae Pentref Tudweiliog yn sefyll a'r fryn bach, sydd wedi ei amgylgylchynu a thir porri isel, ar arfordir Gogleddol Llŷn. Mae wedi ei leoli ar y B4417 rhwng Edern a Llangwnadl, wrth ochr afon Amlwch, a tua 1km oddi wrth yr arfordir a thraeth Porth Tywyn.

The village of Tudweiliog sits on a small hill surrounded by low lying pasture land on the North coast of Llŷn. It lies on the B4417 between Edern and Llangwnnadl. It is situated near the river Amlwch about 1Km from the coast and beach at Porth Towyn.