The Castle of Almourol is a XII century medieval castle atop the islet of Almourol in the middle of the Tagus River, located in the civil parish of Praia do Ribatejo, 4 kilometres (2.5 mi) from the municipal seat of Vila Nova da Barquinha, in Portugal's Centre Region.
The castle was part of the defensive line controlled by the Knights Templar and one of the best representations of their influence in Portugal.