Aigüestortes i Estany de Sant Maurici National Park (Catalan: Parc Nacional d'Aigüestortes i Estany de Sant Maurici, Spanish: Parque Nacional de Aiguas Tortas y Lago de San Mauricio), is one of the fifteen Spanish national parks, and the only one located in Lleida, Spain.
A wild mountain region in the Pyrenees, with peaks rising to 3017 m (Besiberri Sud) and with nearly 200 lakes, many of them of glacial origin, the park comprises a core area of 141 km2 and a buffer zone of 267 km2 surrounding the park. The park's name in Catalan is Aigüestortes i Estany de Sant Maurici, freely translated as "The winding streams and St. Maurice lake".
The park has an elevation range of 1600 to 3000 metres and contains four major vegetation zones: lower montane, upper montane, subalpine and alpine.
The fauna includes Pyrenean chamois, brown bear, marmot, ermine, roe deer, among other mammals and numerous birds (black woodpecker, common crossbill, lammergeier, golden eagle).
The park was created in 1955 after Ordesa y Monte Perdido National Park, first Spanish national park in the Pyrenees in 1918. Its administrative seats are in Espot and Boí. The park is mainly located in the comarques of Pallars Sobirà and Alta Ribagorça.