Mark Baker (born March 20, 1994) is the seventh child of the Baker family.
Mark is 9 years old, and he is shy. Mark feels left out of his family, as he looks different and claims that he doesn't fit in. His nickname of the film was Fed-Ex, given by his older sister Sarah. He gets bullied at his new school. Mark has a frog named Beans who dies, so he runs away towards the end of the movie. When Mark is found, Jessica explains that his appearance and differences could have been given to any of his siblings. Jake says that "without [him], they wouldn't be the twelve Bakers anymore; they'd be eleven." Mark returns home and has a closer relationship with his family. Mark is not shy after returning home.