Grey's Thirteenth Investigation (French: La treizième enquête de Grey) is a 1937 French crime film directed by Pierre Maudru and starring Maurice Lagrenée, Raymond Cordy and Colette Darfeuil.

[1] It was based on play by Max Viterbo, inspired by the character of Inspector Grey created by Alfred Gragnon.

[2] It was the third of series of four films featuring the detective.

The film's sets were designed by the art director Lucien Carré.

This article related to a French film of the 1930s is a stub.