Mary Lynn is the secondary antagonist of the 2006 film Unaccompanied Minors. She is portrayed by Michelle Sandler.
She is not actually evil, but is very selfish and only pretends to be nice to Katherine Davenport. She braids her hair, gives her a makeover and tries to brush her teeth once the adults are not around. Later that night, while she's sleeping and snoring loud, Katherine quietly sneaks out and goes down to meet Santa by 4:30 am. When Katherine's brother Spencer asks Mary Lynn if she's in there she asks who wants to know and Spencer tells her that her brother wants to know. She then crosses her arms thinking that she's not allowed to talk to strangers but luckily Grace scares her off.
She makes her final appearance when she and the other unaccompanied minors are coming back to the airport on Christmas Day.