Greg Whittington added 13 points as the Hoyas (3-0) advanced with the tournament semifinal victory. Porter also hauled down 11 rebounds to go with five assists.
Georgetown will now advance to face top-ranked Indiana in Tuesday's championship game of the tournament at Barclays Center in New York.
The Bruins (3-1) were led by Jordan Adams with 22 points and six rebounds.
Travis Wear contributed 12 points and eight rebounds for UCLA.