The arrondissement of Lens is an arrondissement of northern France in the Pas-de-Calais department in the Hauts-de-France region.

[2] Its population is 369,427 (2021), and its area is 351.5 km2 (135.7 sq mi).

[4][5] In January 2007 it absorbed the two cantons of Avion and Rouvroy from the arrondissement of Arras.

[6] As a result of the reorganisation of the cantons of France which came into effect in 2015, the borders of the cantons are no longer related to the borders of the arrondissements.

The cantons of the arrondissement of Lens were, as of January 2015:[7]