A brief functional analysis was conducted in an analogue setting to identify the maintaining variables for upright walking in a woman with developmental disabilities supported in an outpatient setting. All conditions required modification, since treatment outcomes were intended to increase, rather than decrease, the target behavior. The participant displayed a significantly greater duration of upright walking during the attention condition, which initially indicated that the desired behavior was maintained by positive reinforcement. Treatment of socially stigmatizing ambulation was implemented during natural transition times in a reversal design and consisted of differential reinforcement of an incompatible response. Results of treatment indicated that physical assistance delivered by staff produced an immediate and large increase in upright walking while verbal attention from staff was ineffective. During treatment conditions, duration of socially stigmatizing ambulation was significantly greater in baseline. These results indicate that socially stigmatizing ambulation was maintained by automatic reinforcement, rather than socially or access-based positive reinforcement, and treatment initially chosen to function as differential reinforcement of incompatible behavior may have also functioned as sensory matching and sensory extinction. (Contains 3 figures.)