Anta da Toupeira, Chalcolithic dolmen in Lousa, Portugal.

Anta da Toupeira is a Chalcolithic dolmen in Lousa, Loures, consisting of a polygonal chamber about 5.5 by 5 metres and up to 2 metres high. Five limestone slabs remain, one thought to have been the roof. It sits on a plateau above the Salemas cave, hidden by trees.

The dolmen dates to the Chalcolithic, not the Neolithic. It was probably identified by Carlos Ribeiro in the 19th century, drawn by Georg and Vera Leisner on 17 January 1944, and first excavated in November 1959 by Vera Leisner and O. V. Ferreira, who corrected the earlier plan.

The finds linked to the site include a cylindrical idol, an axe of amphibole, a copper chisel, a copper arrowhead and a pendant, now held at Lisbon's Geological Museum. Archaeologists are unsure whether they came from the dolmen, the nearby Cave of Salemas, or a second anta mentioned by the Leisners but never relocated.

The dolmen sits on the plateau above the Gruta de Salemas, about 100 metres south of the cave, hidden by a clump of trees. From Salemas, cross the Lisbon–Torres Vedras motorway and continue roughly 700 metres to the slope, where the cave fissure opens a few metres from the quarry path. The five surviving slabs stand in the open; no facilities or protection are in place.

The Leisners noted a second anta nearby that has never been relocated. Finds from the 1959 excavation—a cylindrical idol, an amphibole axe, a copper chisel, a copper arrowhead and a pendant—are at Lisbon's Geological Museum, though their exact origin between the anta and the cave remains uncertain.