Marissa has two children, had her first baby at the end of August 2004, a baby boy named Cosimo Henri. and a second baby in April 2007.
Marissa is married to Beck since 3 April 2004.
Marissa and her twin brother Giovanni Ribisi were both delivered by Bibbe Hansen, Beck's mother.
Marissa is a Scientologist.
Marissa was a contestant on I'm Telling! with her twin brother Giovanni Ribisi in 1987. They came in third place.
Marissa: Before Scientology my life seemed direction-less. I knew there were things I wanted to accomplish in life, but I didn't know how to get there or where to start. I was worried. I worried a lot, even at a young age. My brother is an actor and at that time he had already had many successes in acting. I knew that 's also where I wanted to go with my life, but I just couldn't pick myself up and do it. I also wanted to write but I had this idea "I'm just not creative in that area".