A protocol officer was a crewmember aboard Starfleet vessels in the 22nd century responsible for ensuring that the various rules and regulations aboard ship were known and followed.

Aboard Enterprise NX-01, Communications Officer Hoshi Sato fulfilled this role. In 2154, Captain Archer informed Navaar, an Orion slave girl who had been brought on board, that Sato would be discussing ship's operations with her; specifically, which areas of Enterprise were off limits to non-Starfleet personnel. (ENT: "Bound")

Sato's position as protocol officer aboard Enterprise was also listed in a personnel file about her, in the library computer onboard the Federation starship USS Defiant. (ENT: "In a Mirror, Darkly, Part II", display graphic)