Laurence Luckinbill (born November 21, 1934) is an American actor. He starred in the 1976 Broadway play Poor Murderer. He portrayed Spock's half-brother Sybok in Star Trek V: The Final Frontier (1989). He also appeared in The Boys in the Band, reprising the part of Hank, which he originated on stage. Other film appearances include Such Good Friends, Cocktail and The Promise, and he has been seen in numerous television shows, including Law & Order, Barnaby Jones, Columbo episode Make Me a Perfect Murder and Murder, She Wrote.
His acting career has also included writing and directing. He has written and performed in several one-man shows including, Hemingway, Teddy, An Evening with Clarence Darrow, as well as, Lyndon, which he did not write, but has performed numerous times, including a schedule at the LBJ Museum in Austin, Texas, where Lady Bird Johnson was one of those in attendance.