The Commercial Titan III, also known as CT-3 or CT-III, was an American expendable launch system, developed by Martin Marietta during the late 1980s and flown four times during the early 1990s.

It was derived from the Titan 34D, and was originally proposed as a medium-lift expendable launch system for the US Air Force, who selected the Delta II instead.

Due to higher costs than contemporary rockets such as the Ariane 4, orders were not forthcoming, and the CT-3 was retired in 1992.

[citation needed] The launch received the International Designator 1990-001, using the UTC date.

Astronauts attached a new kick motor, which raised the satellite into a geosynchronous transfer orbit, as had originally been planned.