Simmons and Tweed tied the knot before 400 guests, including their two children, Nick, 22, and Sophie, 19, at The Beverly Hills Hotel.
The couple's long relationship has not been without its tribulations. Last summer, Tweed walked out on Simmons during a taping of HLN's "Joy Behar Show" after her longtime partner joked about the number of women he'd been with in the past.
The star of the A&E reality series, "Gene Simmons Family Jewels," Simmons proposed to his longtime girlfriend in Belize, saying, "I come with so much baggage, but you're the only friend I've got, you're the only one I've ever loved." The proposal came July 26, on the show's season finale.
Notable guests at the festivities included Hugh Hefner, Bill Maher, and Duane "Dog the Bounty Hunter" Chapman.