Transformative learning (TL) is an important component of sustainable volunteer tourism experiences, potentially reducing unsustainable outcomes, and educating and enlightening volunteers. This paper reviews theories and issues about TL in volunteer tourism, and analyzes data from 1008 useable responses to an online survey of potential volunteer tourists. A factor-cluster analysis of potential volunteer tourists' motivations identified key volunteer tourist segments and assessed differences in expectations of TL across each segment. Altruism remains the primary motivation, with personal development an expectation, but the study also found desires to experience different cultures, build relationships with family, and to escape one's daily life. Three motivation segments emerged: Volunteers, Voluntourists, and Tourists. Differences in the three clusters' expectations for TL were assessed through multiple analysis of variance using items representing Taylor's three elements of TL: self-reflection, engaging in dialogue, and intercultural experience.Differences in TL expectations varied significantly across the three segments. Potential Voluntourists were most likely to expect to participate in TL opportunities. The paper concludes with suggestions for maximizing TL for each segment. Volunteers and Tourists may require activities that include different, less obvious forms of TL. Volunteer tourism organizations need to invest significantly in staff training in TL.