"They got Lang, sir."
– Kelowitz, 2267 ("Arena")

Lieutenant Commander Lang was a male Human Starfleet officer who lived during the mid-23rd century. He served in the command division aboard the USS Enterprise under Captain James T. Kirk as one of the ship's gunnery officers.

In 2267, Lang was one of three tactical aides, along with O'Herlihy and Kelowitz, who beamed to the Earth observation outpost on Cestus III in 2267. Arriving, they discovered the colony had been destroyed by the Gorn, a previously unknown species. Captain Kirk ordered Lang to look for survivors, and upon the discovery of the Gorn's position, Kirk ordered Lang and Kelowitz to "flank out [and] [l]ay down fire on coordinates Mr. Spock gave you. Even if you don't see them. Keep your heads down." Shortly after this, Lang did not respond to Kirk's call for assistance with a grenade launcher, and his death was ultimately reported to Kirk by Kelowitz, who arrived in his place. (TOS: "Arena")

Lang was played by actor James Farley, who did not speak during this role. The script of "Arena" gave Lang's shipboard position as "gunnery officer".