A child that used a wheelchair was anecdotally observed to display little aggressive behavior when being pushed in his wheelchair, but higher rates of aggressive behavior when movement was terminated. A functional analysis was conducted to systematically assess the relationship between aggression and wheelchair movement. The functional analysis results revealed elevated rates of aggression when it resulted in being briefly pushed in the wheelchair. This functional hypothesis was subsequently validated by teaching the child to request movement through appropriate means and demonstrating that aggression decreased under treatment conditions. These results extend prior research on functional analysis by demonstrating a previously unreported behavioral function particular to individuals with motor deficits.