Georgetown (25-5) advances to a Big East Tournament semifinal Friday against No. 20 Syracuse, which edged No. 19 Pittsburgh 62-59 later Thursday. Cincinnati waits to see where its 22-11 record places it in post-season play.
Porter's 18 points led a balanced Hoyas attack and Georgetown was in control much of the game.
Cincinnati led just three times -- 1-0, 4-3 and 33-31.
The Hoyas erased the last lead with five points from D'Vauntes Smith-Rivera. After Cheikh Mbodj scored for Cincinnati, Georgetown got baskets from Porter and Markel Starks for a 42-35 advantage and the Hoyas pulled away.
Cincinnati overcame a horrid start to make a game of it through the early sections of the second half. The Bearcats made just one of their first nine shots and trailed by as much as 16 points in the first half.
Cincinnati, however, used 3-point shooting to get within 29-24 by halftime and led 33-31 before Georgetown started to consistently pull away.
Porter was 11-of-11 from the free-throw line in taking scoring honors. Starks added 14 and Smith-Rivera 13 for Georgetown.
Cashmere Wright, who was 4-of-5 from 3-point range, led Cincinnati with 14 points.