A self-styled club of command-hungry ensigns aboard the USS Cerritos who practise looking and sounding like captains, and who briefly take Brad Boimler into their ranks.
The Redshirts are a group of junior officers in the Lower Decks episode The Spy Humongous. Led by Ensign Casey, they wear the red of the command division and are convinced that the route to the captain's chair lies in copying the manner of the bridge crew.
They invite Boimler to join after his service on the USS Titan, give him a new haircut and coach him in power poses and stirring speeches. He is flattered enough to drop his friends, who are stuck on a rubbish-collecting detail.
The test comes when Tendi is turned into a rampaging creature by a strange artefact. The Redshirts try oratory and achieve nothing. Boimler instead makes a fool of himself to make her laugh, which calms her, and when the others sneer at such undignified conduct he walks away from them.