Psychotherapy is a culturally encapsulated healing practice that is created from and dedicated to specific cultural contexts (Frank & Frank, 1993; Wampold, 2007; Wrenn, 1962). Consequently, conventional psychotherapy is a practice most suitable for dominant cultural groups within North America and Western Europe but may be culturally incongruent with the values and worldviews of ethnic and racial minority groups (e.g., D. W. Sue, Arredondo, & McDavis, 1992). Culturally adapted psychotherapy has been reported in a previous meta-analysis as more effective for ethnic and racial minorities than a set of heterogeneous control conditions (Griner & Smith, 2006), but the relative efficacy of culturally adapted psychotherapy versus unadapted, bona fide psychotherapy remains unestablished. Furthermore, one particular form of adaptation involving the explanation of illness--known in an anthropological context as the illness myth of universal healing practices (Frank & Frank, 1993)--may be responsible for the differences in outcomes between adapted and unadapted treatments for ethnic and racial minority clients. The present multilevel-model, direct-comparison meta-analysis of published and unpublished studies confirms that culturally adapted psychotherapy is more effective than unadapted, bona fide psychotherapy by d = 0.32 for primary measures of psychological functioning. Adaptation of the illness myth was the sole moderator of superior outcomes via culturally adapted psychotherapy (d = 0.21). Implications of myth adaptation in culturally adapted psychotherapy for future research, training, and practice are discussed. (Contains 1 figure and 4 tables.)