A three-component multiple-schedule and brief reversals were used to examine the effects of differential reinforcement of other behavior (DRO) and noncontingent matched stimulation (NMS) on the automatically reinforced mouthing of a child with autism. Both DRO and NMS decreased immediate engagement in mouthing, but NMS produced larger reductions in the behavior. Furthermore, NMS produced subsequent effects (i.e., when the treatment was withdrawn) similar to those of prior access, whereas DRO marginally increased subsequent engagement in mouthing. The results suggest that NMS was a functionally matched intervention for mouthing. Implications for the assessment and treatment of stereotypy and applications for future research are discussed. Copyright © 2010 John Wiley & Sons, Ltd.