Mia, portrayed by Emmanuelle Vaugier, met Charlie at a cafe while she was reading a magazine. Mia was Charlie's first serious relationship. Mia tries to make Charlie take up a healthier lifestyle, giving up cigars, beer, meat, and making him take jogs with her. Charlie kept doing all these things in secret, and when Mia discovered them, they broke up. Mia leaves and then later in the season comes back. Charlie proposes and when the couple goes to Vegas, to get married, Mia asks if Charlie will be kicking Alan out of the house and Charlie refuses to evict Alan - so Mia breaks off the engagement.
Mia makes apperances in seasons five, six and seven. In season seven, when Mia tries to rekindle the flame, Charlie chooses to stay with Chelsea.