Boxer's campaign said Wednesday that the vice president will participate in a July 8 fundraiser in Silicon Valley and another in Los Angeles the following day.
Biden is the latest Democratic headliner to come to the aid of the three-term senator, who faces Republican Carly Fiorina in the general election.
President Barack Obama has flown to California twice in recent months to help the incumbent's fundraising efforts. First lady Michelle Obama appeared with Boxer last week at a Camp Pendleton event in support of troops.
No other details about the vice president's visit were available.