Consistent with evidence-based practice guidelines, clinicians are expected to take client variables into account, especially when selecting among treatment options that are equivalent in their levels of empirical support (Kazdin, 2008). Client preference is one such variable to be considered in the treatment selection process. The purpose of this analogue study was to further investigate the putative role of client treatment preference as a moderating variable of therapeutic responsivity. Participants reporting a moderate fear of spiders completed an approach task after receiving a brief preferred or nonpreferred treatment protocol reflective of either traditional cognitive-behavioral therapy or acceptance and commitment therapy (ACT). Contrary to expectations, participants who received their preferred treatment, by either choice or random assignment, did not differ in their progression through and subjective reactions to the behavioral approach task from those who were presented with their nonpreferred option. The hypothesis that any main effect between the two treatment protocols would favor ACT was supported, but a predicted interaction with participant preference was not. Factors that may have contributed to both anticipated and unanticipated findings are discussed as well as the implications for further research and clinical practice involving client treatment preference.