Nature Park of Arrábida, Nature reserve in Setúbal Peninsula, Portugal.

Arrábida Natural Park covers 176.41 km² of the southern margin of the Setúbal Peninsula, with 123.30 km² on land and 53.11 km² at sea. Its centre is the Serra da Arrábida, a limestone massif reaching 501 m at Formosinho, running about 35 km long and 6 km wide. The range meets the Atlantic in cliffs such as Serra do Risco, while beaches like Galapinhos, Portinho da Arrábida and Figueirinha lie below.

Protection began with Decree 355/71 of 16 August 1971, which created the Arrábida Reserve covering the southern mountain flanks and the Risco cliffs. Decree 622/76 of 28 July 1976 then established the Parque Natural da Arrábida to safeguard its geology, forest, wildlife and landscapes. A regulating decree of 14 October 1998 reclassified the park, extended the coastal area and set up the Arrábida-Espichel Marine Area. In 2025 UNESCO designated it a biosphere reserve.

The park's name comes from the Serra da Arrábida, the limestone ridge at its centre. Above the beaches of Galapinhos, Portinho da Arrábida and Figueirinha stands the Convent of Our Lady of Arrábida, a former monastery founded in the 16th century and now managed by the Fundação Oriente. The marine area off Cabo Espichel was added in 1998 to protect coastal cliffs, endemic plants and seabird nesting sites.

The park covers 176.41 km², of which 53.11 km² is marine area added in 1998 as the Arrábida-Espichel Marine Area. The three beaches overlooking the Convent of Our Lady of Arrábida — Galapinhos, Portinho da Arrábida and Figueirinha — are the busiest spots, drawing visitors from Lisbon and Setúbal. The massif runs about 35 km east-northeast to west-southwest and is 6 km wide, so plan walks around the limestone ridges rather than across them.

The Arrábida breccia, a sedimentary rock quarried in the massif, is known as Arrábida Marble and was used as an ornamental stone. The park also holds the Gruta do Frade, a karst cavity, and fossil deposits with fragments of sauropod dinosaurs, notably near Cabo Espichel.