Sarek /ˈsærɛk/ is a fictional character in the Star Trek media franchise. He is a Vulcan astrophysicist, the Vulcan ambassador to the United Federation of Planets, and father of Spock. The character was originally played by Mark Lenard in the episode "Journey to Babel" in 1967. Lenard later voiced Sarek in the animated series, and appeared in Star Trek films and the series Star Trek: The Next Generation.

Actor Jonathan Simpson played a younger Sarek in a brief scene in Star Trek V: The Final Frontier, with voice-over provided by Lenard. Ben Cross portrayed Sarek in the 2009 Star Trek film. James Frain plays Sarek in the television series Star Trek: Discovery.

The character appears in the original Star Trek series, the animated series, five Star Trek films, two episodes of Star Trek: The Next Generation, Star Trek: Discovery and numerous Star Trek novels and comics.

Sarek was born in 2165. He is the son of Skon of Vulcan and the grandson of Solkar (the first Vulcan ambassador to Earth). Sarek was married twice, and had two sons. Prior to his first marriage, he had a relationship with a Vulcan princess which produced Sarek's first son Sybok, a character not developed until the fifth feature film in the late 1980s. Sarek later married Amanda Grayson, a native of the planet Earth, with whom he had Spock. After Amanda's death, Sarek married Perrin, also human, who survived his death. Sarek and Perrin had no children together.

Sarek's second son, Spock, entered Starfleet Academy. Sarek opposed the decision because he wanted Spock to enter the Vulcan Science Academy which he had arranged for years before and the two were estranged for 18 years. Following a mission on the Enterprise where Spock helped save Sarek's life, father and son are reconciled in the episode "Journey to Babel", with Mark Lenard portraying the first appearance of Sarek.

Mark Lenard voiced Sarek in the Star Trek: The Animated Series episode "Yesteryear". In this episode Spock must travel back in time to his childhood, and keep his younger self from dying and being replaced by an Andorian as First Officer of the Enterprise. Spock, posing as a relative, meets a younger version of Sarek.

Mark Lenard portrayed Sarek in movies based on the original Star Trek series. In Star Trek III: The Search for Spock (1984), Sarek confronts James T. Kirk at his apartment, thinking that Spock placed his katra, or living essence, into Kirk's mind (since Kirk was the last person to be with the dying Spock), and asking Kirk why he did not return Spock to Vulcan. Unknown to either Sarek or Kirk, Spock had actually placed his katra in the mind of his friend Leonard McCoy for safekeeping. Kirk later discovers this through the security tapes during the last moments of Spock's life in his fight to save the Enterprise from Khan. Sarek asks Kirk to bring Spock's body back along with his katra to Vulcan; Kirk promises to do so. The Genesis Device regenerates Spock's body and restores his life; Kirk and his crew manage to get Spock off the planet and return him to his home planet of Vulcan. There, Sarek asks the priestess T'Lar to perform a fal-tor-pan, reuniting Spock's mind and body. Sarek thanks Kirk for the rescue of Spock, which took place at the expense of the destruction of the Enterprise and the death of Kirk's son. Kirk admitted if he did not try to save Spock, he would have faced a deeper guilt in his soul.

Star Trek IV: The Voyage Home (1986) begins with Kirk, Spock, and the rest of the Enterprise crew still in exile on Vulcan. Sarek travels to Earth to speak on behalf of Kirk (who is facing charges from the Klingon Empire), and is subsequently trapped on the planet when Earth is threatened by destruction by an alien probe. After Kirk and his crew return and save Earth, and are largely exonerated at their subsequent trial, Sarek has a private audience with his son. Sarek states that he is pleased with Spock, and admits that he was wrong in opposing Spock's induction into Starfleet, praising his comrades as people of good character.