The 12"/50 caliber Mark 7 gun was a United States Navy's naval gun that first entered service in 1912. Initially designed for use with the Wyoming class of dreadnought battleships, the Mark 7 also armed the Argentine Navy's Rivadavia-class battleships.

The Wyoming class was a pair of dreadnought battleships built for the United States Navy. Wyoming and Arkansas were authorized in early 1909, and were built between 1910 and 1912. These were the fourth dreadnought design of the US Navy, but only an incremental improvement over the preceding Florida class, and the last US battleships to use 12-inch guns. The primary changes were the adoption of a more powerful 12 in (305 mm)/50 caliber Mark 7 gun, addition of a sixth twin-gun turret and improved armor protection, including the first use of a torpedo bulkhead on American battleships. The Navy considered using more powerful 14-inch (356 mm) guns, but this would have caused delays and required larger docks.