The Canon de 138 mm Modèle 1910 was a medium calibre naval gun of the French Navy used during World War I and World War II. It was carried by the dreadnoughts of the Courbet and Bretagne classes as their secondary armament and planned for use in the Normandie-class battleships. It was used as the primary armament for the Arras-class sloops and planned for the La Motte-Picquet-class cruisers that was cancelled in 1915. It was also used in coast defense batteries during both World Wars.

The Courbet-class battleships were the first dreadnoughts built for the French Navy. These were completed prior to WWI. The class comprised four ships: Courbet, France, Jean Bart, and Paris. All four ships were deployed to the Mediterranean Sea for the entirety of World War I, spending most of their time escorting French troop convoys from North Africa and covering the Otranto Barrage. An Anglo-French fleet led by Courbet succeeded in sinking the Austro-Hungarian protected cruiser Zenta in the Battle of Antivari. Jean Bart was torpedoed in the bow by U-12 on 21 December 1914, but she was able to steam to Malta for repairs.