- Klingons and Federation sign a peace treaty which they honor over the next three years.(TOS: "Day of the Dove")
- Captain James T. Kirk assumes command of the USS Enterprise for an historic five-year mission of exploration. He is seen off on his first mission as commander of the starship by his brother Sam and his family. His father is also proud to see him off. Prior to assuming command, Kirk's emotional structure is tested by the Robbiani dermal-optic test. (TOS: "What Are Little Girls Made Of?", "The Menagerie, Part I", "Turnabout Intruder"; Star Trek; VOY: "Q2")
- A vintage of Dom Pérignon is made. A bottle from this year's vintage will be used in the christening of the USS Enterprise-B in 2293. (Star Trek Generations)
- The Enterprise becomes one of the first Earth ships to reach the edge of the Milky Way Galaxy, where they encounter the galactic barrier. Gary Mitchell and Elizabeth Dehner are among the Enterprise officers who die in the line of duty. (TOS: "Where No Man Has Gone Before")
- At a Christmas party held in the Enterprise science lab, Captain Kirk meets Dr. Helen Noel. She later recalls him "dropping in" on the party, during a mission to the rehabilitation colony on Tantalus V. (TOS: "Dagger of the Mind")
- Ingraham B is attacked by flying parasites. (TOS: "Operation -- Annihilate!")
- Carter Winston dies on the planet Vendor. (TAS: "The Survivor")
- The Borg "swarm through" the El-Aurian system, invading and destroying the El-Aurian homeworld. The survivors flee and are scattered over the entire galaxy, with some reaching Earth 28 years later. (TNG: "Q Who", Star Trek Generations)
- A new uniform is introduced for Starfleet personnel, though the previous style continues to be used for years. These new uniforms remain in service until the early 2270s. (TOS: "Dagger of the Mind", "Friday's Child"; TAS: "The Counter-Clock Incident"; Star Trek: The Motion Picture)
- Captain Christopher Pike is promoted to the rank of fleet captain. (TOS: "The Menagerie, Part I")
- Uhura begins her Starfleet career. (Star Trek III: The Search for Spock)
- April Wade is born. (DS9: "Prophet Motive")
- Nancy Crater is killed by planet M-113's last surviving native. (TOS: "The Man Trap")
- The pilot episode "Where No Man Has Gone Before", produced in 1965, is the only production set in this year.
- According to the script for Star Trek II: The Wrath of Khan, David Marcus was born in this year.  However, in the script for Star Trek III: The Search for Spock – commonly conjectured to be set in 2285 – David was described as being in his mid-twenties. 
- According to the Star Trek: Star Charts (p. 52), an Earth colony was founded on Cestus III.