Coach Mark Fox announced Tuesday the 6-foot-10 Thompkins was hiring an agent, ending his college eligibility.
"I have spoken with my family and coaches about my situation, and I feel that it's best for me to forgo my senior season and enter the NBA draft," Thompkins said. "I would just like to thank everyone who has supported me in this decision."
Leslie is also entering his name to the list of underclassmen draft prospects. But the 6-4 guard won't hire an agent, giving him the option of returning for his final college season after he evaluates his draft status.
With Thompkins and Leslie leading the way, Georgia reached 20 wins and earned only its second NCAA bid since 2002. The Bulldogs were defeated in the opening round by Washington.
Thompkins led the Bulldogs in scoring and rebounding each of the past two years. He finished his career 13th on the school list in points (1,396) and 10th in rebounds (693).
"We certainly appreciate Trey's contributions to the program and we wish him well in the pursuit of his dreams," Fox said.
Leslie averaged 14.4 points and 7.2 rebounds this past season.
"Travis has exercised his right to test the waters as a junior," Fox said. "We will help him manage that process in a timely manner."
The deadline for underclassmen to withdraw their names from the draft and preserve eligibility is May 8. The NBA draft will be held June 23.