John Sidney McCain, Jr. (1911-1981) was an Admiral in the United States Navy. His father John S. McCain, Sr was also an admiral in the Navy, and his son John S. McCain III is a US Senator representing Arizona.

Born in Council Bluffs, Iowa, he graduated from the United States Naval Academy in 1931.

During World War II, "Junior" commanded the submarines USS Gunnel and Dentuda. Subsequently he held a number of posts, rising to CINCPAC before retiring in 1972.

He was involved in the investigations that followed the Israeli attack on USS Liberty.

He is buried in Arlington National Cemetery.