Penrice Castle (Welsh: Castell Pen-rhys) is a castle near Penrice, Swansea on the Gower Peninsula, Wales.
Penrice Castle is the 13th century successor to a strong ringwork to the southeast, known as the Mountybank. It was built by the de Penrice family who were originally given land at Penrice for their part in the Norman conquest of Gower. The last de Penrice married a Mansel in 1410 and so the castle and its lands passed to the Mansel family. The Mansels later bought Margam Abbey, which they made their main seat while retaining their Gower lands. In the 17th century the castle was damaged in the English civil war.
The stone castle is a large, very irregular hexagon with a round keep on the west side, to which were attached two other towers and a partial mantlet or chemise wall. At the northwest corner is a twin square towered gatehouse with another tower in the interior. The ground falls away steeply on the north, east, south and southwest sides, where there are various other turrets, though not very scientifically disposed. The whole structure is now in a dangerous condition, but the south wall can be seen from the footpath that runs past the 18th-century mansion on the estate (51°34′27″N 4°10′15″W / 51.5742°N 4.1707°W), immediately to the south.