Acceptance and Commitment Therapy (ACT) has previously been shown to alter stigmatizing attitudes and to be relatively useful for psychologically inflexible participants. The present study is the first to bring those two findings together by comparing ACT to an education intervention for reducing stigma toward people with psychological disorders, and examining whether results differ for psychologically inflexible versus flexible individuals. A sample of college students (N = 95) was randomly assigned to a 2 ½ hour ACT or educational workshop. Measures were taken before and after the workshop and at a one-month follow-up. ACT reduced mental health stigma significantly regardless of participants’ pre-treatment levels of psychological flexibility, but education reduced stigma only among participants who were relatively flexible and non-avoidant to begin with. Acceptance could be an important avenue of exploration for stigma researchers