Puerto Madryn (Spanish pronunciation: [ˈpweɾto ˈmaðɾin]; Welsh: Porth Madryn), usually known as Madryn, is a city in the province of Chubut in Argentine Patagonia. It is the capital of the Viedma Department, and has about 103,175 inhabitants according to the last census in 2022.

Puerto Madryn is protected by the Golfo Nuevo, which is formed by the Península Valdés and the Punta Ninfas. It is an important centre for tourists visiting the natural attractions of the Península Valdés and the coast.

The name of the city conmemorates Love Jones Parry, one of the colonizers of Patagonia. The toponym originated around 1863, when Love Jones Parry, along with Lewis Jones travelled to Patagonia aboard Candelaría to decide whether that region was adequate for a Welsh colony.

A new shopping mall in the city centre has helped tourism develop significantly, making Puerto Madryn a more attractive place for both international and domestic tourists visiting Patagonia. It is twinned with Nefyn, a small town on the Llŷn Peninsula in North Wales, the result of its enduring link with Welsh culture since the Welsh settlement in Argentina. The first of a two-Test tour to Argentina by the Wales national rugby union team was played in 2006 in Puerto Madryn, a 27–25 win for Argentina. Puerto Madryn is home to two football clubs; Club Social y Atlético Guillermo Brown, who play in Nacional B and Deportivo Madryn that currently play in Torneo Argentino B.

A basketball team, Deportivo Puerto Madryn, plays in the Liga Nacional de Básquetbol (LNB). Their home arena is known as the Deportivo Puerto Madryn Arena.

El Tehuelche Airport is located 10 km (6 miles) northwest of the city centre. Commercial flights from Buenos Aires, Ushuaia, and other Argentinian cities are available. Most tourists fly into Trelew Airport as flights into Puerto Madryn are restricted as a result of environmental concerns.