Arrentela is a former civil parish in the municipality (concelho) of Seixal, Lisbon metropolitan area, Portugal. In 2013, the parish merged into the new parish Seixal, Arrentela e Aldeia de Paio Pires. The population in 2011 was 28,886, in an area of 10.17 km². It is situated on the south side of the estuary of the river Tagus.