This study evaluated the effectiveness of an 8-session Acceptance and Commitment Therapy for OCD intervention in a nonconcurrent multiple-baseline, across-participants design. Results on self-reported compulsions showed that the intervention produced clinically significant reductions in compulsions by the end of treatment for all participants, with results maintained at 3-month follow-up. Self-monitoring was supported with similar decreases in scores on standardized measures of OCD. Positive changes in anxiety and depression were found for all participants as well as expected process changes in the form of decreased experiential avoidance, believability of obsessions, and need to respond to obsessions. All participants found the treatment to be highly acceptable. Implications and future directions are discussed.