Opera cake (French: Gâteau opéra) is a French cake. It is made with layers of almond sponge cake (known as Joconde in French) soaked in coffee syrup, layered with ganache and coffee (or Grand Marnier) French buttercream, and covered in a chocolate glaze. Its name originates from its layers resembling the levels of an opera house.

According to Larousse Gastronomique, "Opéra gâteau is an elaborate almond sponge cake with a coffee and chocolate filling and icing." Traditionally, the word Opera is also written on top of the chocolate glaze. Edible gold leaf is sometimes added to the presentation.

An advertisement in Le Gaulois in 1899 offers a "gâteau opéra".

The cake was popularized by the French pâtisserie house Dalloyau, but its origin is unclear. Cyriaque Gavillon claimed to have created the cake there in 1955 and that his wife Andrée Gavillon named it after the Opéra Garnier.

Gaston Lenôtre (1920–2009) claimed he invented the dessert in 1960.