Our Lady Star of the Sea and St Winefride (Welsh: Mair, Seren Y Mor a Santes Wenfrewi) is a Roman Catholic church in Amlwch, a town on the island of Anglesey, north Wales. It was built in the 1930s to a design by an Italian architect, Giuseppe Rinvolucri, using reinforced concrete. The church is in the shape of an upturned boat, reflecting Amlwch's maritime heritage, and is dedicated to Our Lady, Star of the Sea (a title of St Mary) and St Winefride, a Welsh saint.