Ninian Pinkney (17 June 1811, in Hammond-Harwood House, Annapolis, Maryland – 15 December 1877), also spelled Pinckney, was a United States Navy surgeon and medical director.

On 12 February 1840, Commodore Isaac Hull, commanding the squadron, ordered Pinkney to return to the United States, and the assistant surgeon reported his arrival on 24 April.

Commodore Alexander J. Dallas, commanding the Pacific Squadron, granted Surgeon Pinkney permission to return to the United States in February 1844, and he arrived there in April of the same year.

Detached from that medical facility ashore on 9 June 1859, Pinkney received orders to join the screw frigate San Jacinto as she prepared for a cruise to the coast of Africa.

The shortage of assistant surgeons compelled Pinkney to serve on board the U.S. Navy Hospital Ship Red Rover, "where he has been of great service fitting out his department."

Acting Rear-Admiral David Dixon Porter, Commanding the Mississippi Squadron, called Pinkney's presence absolutely necessary...many cases occurring where his great experience as a surgeon enabled him to save life in more than one instance.

Porter used the occasion to dispel any misgivings about the fleet surgeon's "little peculiarities" (Pinkney was known to be of "a 'peppery' nature and stood firmly on his dignity and rights"), writing to Secretary of the Navy Gideon Welles on 30 March 1863 of Pinkney that "...a more zealous, devoted officer to the profession, and to the country, does not exist anywhere..." Soon thereafter, the fleet surgeon directed the provision of new ships fitting out at St. Louis, Missouri, and Cincinnati, Ohio, with medical stores during June, 1863, and later that summer supervised the conversion of a seized Confederate building at Memphis, Tennessee, into a hospital.

Detached from the Washington Navy Yard and retired with that rank on 7 June 1873, Pinkney, who received a doctor of laws degree from his alma mater, St. John's College, Annapolis, in 1873.