Trainees often express anxieties when working with clients from different sociocultural backgrounds. Group supervision can provide a space to address such concerns, including managing culturally related countertransference and understanding sociocultural factors in issues faced by clients. This process requires critical consciousness and discussion of trainees' and clients' cultural identities. This study built on research highlighting the positive role of cultural humility in individual supervision and group therapy to examine cultural humility in group supervision and its contribution to trainees' self-efficacy in adapting therapy and managing relationship conflicts with a range of clients (i.e., cultural responsiveness self-efficacy), via sociocultural awareness and minimal cultural concealment about themselves and their clients. Ninety-one master's level counseling trainees in Hong Kong from 18 supervision groups in two training programs completed measures of cultural humility, cultural concealment, sociocultural awareness, and cultural responsiveness self-efficacy. Multilevel modeling indicated that, at the within-trainee level, higher group cultural humility was associated with higher sociocultural awareness and lower cultural concealment about themselves and their clients. Greater sociocultural awareness, but not cultural concealment, was, in turn, linked to higher cultural responsiveness self-efficacy. At the between-trainee level, higher group cultural humility correlated with lower trainee cultural concealment, but not sociocultural awareness, which was associated with cultural responsiveness self-efficacy, although no mediation was observed. This study underscores the value of cultural humility in the context of group supervision. Implications for multicultural group supervision are discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).