Alenquer (), officially the Town of Alenquer (), is a Portuguese municipality in the Lisbon District and in the Oeste region. The population in 2011 was 43,267, in an area of . The present Mayor is Pedro Miguel Ferreira Folgado.
Alenquer received its Foral in 1212 by the hand of Infanta (Princess) Sancha, Lady of Alenquer, daughter of King Sancho I of Portugal.
The name Alenquer may stem from the Germanic phrase Alan Kerk, meaning "Temple of the Alans." The Alans settled in Lusitania in the early 3rd century AD; the municipality's name is one of the vestiges of their presence that has lasted into the modern world.
Alenquer has a mediterranean climate with hot, dry summers and mild, wet winters. It has a total of 2763.9 annual hours of sunshine.
Administratively, the municipality is divided into 11 civil parishes (freguesias):