Kevin Larsen added 14 points and six rebounds for the Colonials (4-2), who shot 46 percent from the field, won the rebounding battle 37-29 and limited themselves to just 9 turnovers while forcing 21 from UMBC.
Malcolm Brent came off the bench to lead the Retrievers (0-7) in scoring with 15, including hitting 4-of-6 from three point range. Charles Taylor and Will Darley each finished with 10 points for UMBC.
George Washington led 46-34 at halftime, helped in large part by a 12-2 run midway through the first half. The Colonials were never seriously threatened in the second half, pushing their lead as high as 25.