Task Force 173 was a Starfleet task force extant in the late 24th century. It was part of the Starfleet Seventeenth Fleet.
In 2377-78, Commodore Lillian Norris was Task Force 173's commanding officer aboard the flagship USS Adelphi (an Ambassador-class heavy cruiser commanded by Captain Mandar Othera). Task Force 173, deployed on patrol missions, was then homeported at Starbase 193. (Ships of the Star Fleet, Vol. 4: Star Fleet Operating Forces. )