Lisa and Robin Murtaugh are the only twins of Jimmy Murtaugh & Sarina Murtaugh. They each get one line in the movie, when they rebel against their father. Robin tells her father, "We like the Bakers" before diving into the lake. Lisa concurs with her sister, saying, "Yeah Dad" and is the second to last Murtaugh to leave Jimmy sitting in the canoe, diving after her twin sister Robin. They, along with the rest of their family, work together to get Nora Baker-McNulty to the hospital in time. After they get there, they are ordered to wait in the waiting room with the Bakers. Their mother Sarina Murtaugh is seen braiding one of the twin's hair while waiting in the waiting room, while the other twin is seen memorizing facts from flashcards. Robin and Lisa's best friends are Baker twins Kim and Jessica. They are 11 years old.
Lisa and Robin Murtaugh are played by the identical twins Courtney and Madison Fitzpatrick.