Marissa Johnson is the wife of Zack Johnson whom he met in a book shop. She first appears in the season 12 episode "The Propagation Proposition" because she and Zack want to have a baby, but Zack is infertile. They decide to ask Leonard to help them out and Leonard said yes and wanted to help them out. Leonard at first was willing to help them out until he decided he didn't want a child in the world that he and Penny weren't going to raise.
- Marissa works in a bookstore.
- She appears to be no smarter than Zack is.