Potentially salient outcomes of intervention for challenging behavior shown by people with mental retardation (MR) were identified by focus groups and through a literature review. Items generated by this process were subsequently rated by 150 respondents from seven stakeholder groups: 28 people with MR, 9 parents of people with MR, 22 clinical psychologists, 7 psychiatrists, 31 nurses, 33 managers, and 20 direct support workers. Results indicated that reduction in the severity of challenging behavior was considered the most important outcome of intervention for a child/young adult living with his or her family by four of the seven stakeholder groups; reduction in the severity of challenging behavior was considered the most important outcome of intervention for an adult living in a community-based group home by three of the seven stakeholder groups; alternative outcomes considered to be the most important by stakeholder groups included increased friendships and relationships, changes in the perceptions of individuals by others, learning of alternative ways of getting needs met, increased control, and empowerment; there were moderate levels of agreement on the relative importance of outcomes between individual members of stakeholder groups who did not have MR; there were high levels of agreement on the relative importance of outcomes between stakeholder groups of people who did not have MR; and levels of agreement on the relative importance of outcomes between people with MR and members of all other stakeholder groups did not reach the level of statistical significance.