Penmaenmawr (, Welsh: [ˈpɛnmaːɨnmaur] (listen)) is a town and community in Conwy County Borough, Wales, which was formerly in the parish of Dwygyfylchi and the traditional county of Caernarfonshire. It is on the North Wales coast between Conwy and Llanfairfechan and was an important quarrying town, though quarrying is no longer a major employer. The population of the community was 4,353 in 2011, including Dwygyfylchi and Capelulo. The town itself having a population of 2,868 (2011).
It was named after Penmaenmawr mountain, which stands above the sea immediately west of the town. Much of its formerly rounded top (with an old hill-fort) has been quarried away, leaving the present-day lower flat top.