Saint-Ambroise, Catholic church in 11th arrondissement, Paris, France

Saint-Ambroise is a Roman Catholic parish church at 71 Boulevard Voltaire in the 11th arrondissement, built 1863–1868 to Théodore Ballu's designs. Its symmetrical stone facade has two 68-metre towers with octagonal spires, clock faces and pinnacles, a central rose window and three arched portals whose tympana carry enamelled paintings by Giuseppe Devers. Inside, an 87-metre nave of pointed arches on clustered piers rises 20 metres to ribbed vaults, ending in an apse with three blue-glass windows.

A first chapel was built on the site in 1659 by the Annonciades de Popincourt convent. The present church was declared of public utility on 24 January 1863 and built from 1863 to 1868 to Théodore Ballu's designs, after the old church was demolished for the cutting of Boulevard du Prince-Eugène, now Boulevard Voltaire. The first mass was held on 21 March 1869, and Cardinal Léon-Adolphe Amette consecrated the church on 7 December 1910.

The church gave its name to the surrounding quartier Saint-Ambroise. During the 1871 Commune it housed the Club Ambroise, also called the Club des prolétaires, where feminist orators spoke and which published the newspaper Le Prolétaire; from 23 May 1871 it served as a powder and munitions store. The tympana of its three portals carry enamelled-lava paintings by Giuseppe Devers (1823–1882) showing eloquence, theology and Saint Ambrose.

The church stands at 71 Boulevard Voltaire, at the head of the boulevard, with the Saint-Ambroise metro station of line 9 nearby. The main entrance is through the projecting porch with its three doorways; the nave then runs straight to the rounded apse. The square Saint-Ambroise occupies the site of the earlier church, and the Jardin Truillot lies in front of the facade.

The church's bells were blessed on 29 April 1869 in the presence of Empress Eugénie, who was godmother to one of them. The octagonal spires end in iron crosses topped by a weather vane shaped like a rooster, the emblem of the French State.