The former Kentucky coach was introduced at a press conference in Lubbock, Texas, where he takes over for Pat Knight, who was fired March 8 after three disappointing seasons.
"I am so grateful to be the head basketball coach at Texas Tech University," Gillispie said. "This morning (I) signed the contract to make it official and I can't tell you how excited we both are about the future of this program."
"Over the past two weeks I have had the opportunity to spend significant time with Billy and I am absolutely confident that he will lead our basketball program back to the national spotlight while positively representing our university," Texas Tech Director of Athletics Kirby Hocutt added.
Gillispie last coached for the Wildcats, compiling a 40-27 record with the, from 2007-09. He won SEC Coach of the Year honors in 2007-08 but parted ways with the school in 2009 after the Wildcats failed to make the NCAA Tournament for the first time since 1991.