This randomized trial compared a combined Acceptance and Commitment Therapy/Habit Reversal Training (ACT/HRT) to a waitlist control in the treatment of adults with trichotillomania (TTM). Twenty-five participants (12 treatment and 13 waitlist) completed the trial. Results demonstrated a significant reduction in hair pulling severity, impairment ratings, and hairs pulled, along with significant reductions in experiential avoidance and both anxiety and depressive symptoms in the ACT/HRT group compared to the waitlist control. Reductions generally were maintained at a 3-month follow-up. Decreases in experiential avoidance and greater treatment compliance were significantly correlated with reductions in TTM severity, implying that targeting experiential avoidance may be useful in the treatment of TTM. Other implications and suggestions for future research are noted.