The win keeps the Vikings perfect at 17-0 and 11-0 in the Midwest Conference.
Lawrence got a balanced attack, with four players in double figures. Kyle MacGillis scored 19 points to pace Lawrence, and Chris Braier added 12 points and nine rebounds. Keven Bradley and Ryan Kroeger had 11 points apiece.
Bo Johnson led Ripon (6-11, 5-6 MWC) with 19 points.
Lawrence led by as many as 10 points in the first half and held a 68-60 lead with 2:32 left in the contest.
Vehantre Brown hit a 3-pointer for the Red Hawks with 38 seconds left that cut the lead to 68-63. Braier then converted 1 of 2 free throws for Lawrence, but Johnson's layup cut the lead to 69-65.
After a Lawrence turnover, Paul Wise hit a jumper to cut the lead to 69-67, but Kroeger was fouled with 13 seconds left. He hit both free throws, and David McMullen then turned the ball over for Ripon.
Braier was fouled again and sealed the win by hitting a pair of free throws with seven seconds left to put Lawrence up 73-67.
Lawrence, which won on the road for the third time in five days, returns home for a pair of games this weekend. The Vikings host Knox on Friday night and Illinois College on Saturday afternoon.