The Vulcanian Expedition was a Starfleet operation in the early 2250s, centering on the planet Vulcan.

Following complaints from several Federation member states, most notably Tellar, that the pacifist Vulcans did not have enough nationals enlisted in Starfleet, four starships were dispatched to Vulcan and assumed orbit for several days. Officially, the purpose was to demonstrate strength and unity , but in reality, it was intended as an act of intimidation. Following talks with the Vulcan Council, the USS Intrepid was commissioned, and crewed by an all-Vulcan crew, and dedicated to research missions only.

One of the four starships taking part in the Expedition was the USS Republic, with James T. Kirk serving as navigator. Kirk spent some time on Vulcan Space Central, but had no interactions with the Vulcans aboard. In later years, he would reflect on the Vulcanian Expedition as the closest he had ever come to dealings with Vulcans prior to meeting First Officer Spock of the USS Enterprise. (TOS novel: Strangers from the Sky)