Chell is a fairly young, thin woman who appears to be of multiracial descent. She has light brown skin, dark hair with streaks of grey, and grey eyes. Her split earlobes suggest that she once wore earrings that were violently ripped out.
Throughout the first game, she wears a worn-out orange jumpsuit and has bare feet, with Advanced Knee Replacement prostheses surgically attached to her legs.
In Portal 2, her knee replacements have been replaced with Long Fall Boots. She wears the same jumpsuit, but with the upper part folded down and tied around her waist, revealing a white tank top bearing the Aperture logo and tight-fitting pale blue shorts or pants. She also wears a white wrap up past the wrist on her right hand, presumably to provide joint support while holding the Portal gun.