Lamas has been married five times and has six children. His first marriage was to Victoria Hilbert (1981–1982). His second marriage (1983–1985) was to his publicist, Michele Cathy Smith, with whom he had two children: son Alvaro Joshua "A.J." (b. 1983) and daughter Shayne (b. 1985), both actors. Lamas was then in a relationship with actress Daphne Ashbrook; the couple had a daughter, Paton Lee (b. 1988). She likewise is an actress.
Lamas was married to his third wife, Renegade co-star Kathleen Kinmont, from 1989 to 1993. Playmate of the Month Shauna Sand (who made guest appearances in Renegade) became Lamas' fourth wife in 1996. The couple had three daughters—Alexandra Lynne (b. 1997), Victoria (b. 1999), and Isabella Lorenza (b. 2001)—before divorcing in 2002.After five months of dating, Lamas married his fifth wife, Shawna Craig, 2011 in Cabo San Lucas, Mexico. He told reporters that he would change his name to Lorenzo Lamas-Craig. This decision was motivated by the fact that his previous wife, Shauna, kept the surname Lamas, and is legally named Shauna Lamas, and new bride Shawna, whose given name is a homonym and almost identical to that of Shauna, did not wish to have a virtually identical full name. In June 2018, Lamas filed for divorce from his fifth wife citing irreconcilable differences.Lamas started dating a woman named Kenna Scott in April 2020. The couple got engaged in Las Vegas in February 2021. The wedding was set to take place in Napa Valley in May 2022.
Lamas enjoyed close friendships with his Falcon Crest co-stars Ana Alicia and Jane Wyman. He continually praised
Wyman's professionalism and credited her as a "huge influence" on his life and career. After Wyman's death in 2007, Lamas released a statement: "Next to my parents, Jane was the most influential person in my young career. She has left an incredible body of work and accomplishments that cannot go without being recognized and celebrated. I will miss her greatly."Lamas' stepmother, Esther Williams, died on June 6, 2013, at the age of 91, in Los Angeles, California. He stated on Twitter: "The best swim teacher and soul mom RIP."Lamas published his autobiography, Renegade at Heart (co-written by celebrity biographer Jeff Lenburg) in December 2014