A formal reprimand was a disciplinary action taken by Starfleet to officers or Cadets who undertook unauthorized actions.

In 2152, after losing his communicator on a pre-warp planet, Lieutenant Malcolm Reed told his commanding officer Jonathan Archer that he was prepared for any reprimand he would give him due to his carelessness. (ENT: "The Communicator")

In 2154, Commander Charles Tucker teased Malcolm Reed by suggesting that he would file a reprimand for disobeying a direct order. (ENT: "United")

In 2368, Rear Admiral Brand put a formal reprimand in each of Cadets Wesley Crusher, Jean Hajar, Sito Jaxa and Nicholas Locarno's permanent records after they covered up evidence that they participated in an illegal maneuver called the "Kolvoord Starburst", which cost the life of Cadet Joshua Albert. (TNG: "The First Duty")

In 2374, Lieutenant Commander Worf received a formal reprimand from Starfleet Command, after he failed to meet with Dominion informant Lasaran and instead took his injured wife, Lieutenant Commander Jadzia Dax back to Deep Space 9 for treatment. Captain Benjamin Sisko told him that, as Lasaran had information that could have saved millions of lives, Worf would probably never receive the rank of Captain. (DS9: "Change of Heart")

In 2375, Captain Kathryn Janeway put a formal reprimand in Ensign Harry Kim's record, after he had a sexual relationship with Derran Tal. (VOY: "The Disease")