James Thomas Alexander (August 25, 1888 – January 16, 1952) was a United States Navy captain who served as the 37th naval governor of Guam.

He was an outspoken advocate for increased naval power and bases to improve American defensive networks.

[3] In the 1930s, Alexander proved a strong advocate for the strengthening of American sea power as the key to maintaining a healthy national defense.

He recommended various methods to make the island more defensible, including building additional warehouses and harbor facilities, dredging Apra Harbor, constructing a sea wall and oil storage facilities, and the erection of six new officers barracks.

[8] He had to negotiate with the Japanese government in arranging the return of a number of Japanese fisherman who had been rescued when their ship Daichs Saiho Maru sunk in a restricted area of the Guamanian coast.