This article explores the similarities between humanistic (and existential) psychotherapy, represented here by the ideas of Viktor Frankl, Erich Fromm and Irvin Yalom, and Acceptance and Commitment Therapy (ACT). Despite the ongoing dialogue between both therapies during the last decade, regarding both their convergences and divergences, there is a gap in the literature concerning their complementarity in clinical practice. This analysis addresses this gap with the integrative (or pluralistic) clinician in mind, and approximates a theoretical and practical integration anchored upon the transtheoretical model.