Clients often have spiritual needs. Many mental health counselors argue that spirituality should be included in counseling, whereas others contend that religious issues may be beyond the bounds of counselor competence. Though much counselor opinion on spirituality in therapy has been published, little has been published on client desires. Therefore, this study conducted a literature review of research in mental health counseling to examine client expectations and preferences for addressing religion and spirituality in counseling. This manuscript summarizes one of the largest samples of literature on this topic ever reviewed, spanning 64 peer-reviewed journal articles by 148 different authors in 32 different journals, surveying over 64,000 participants, including 4,697 actual counseling clients. We review client-focused research with 4 themes: expectations about spirituality in counseling, preferences for addressing spirituality in counseling, preferences against addressing spirituality in counseling, and the process of spirituality in counseling. Some clients want counseling to address their spiritual issues extensively and expect this to occur, while others prefer these issues to be addressed in the context of other, more primary issues. Still others prefer spiritual issues not to be addressed at all. Client magnitude of spiritual beliefs, client gender, the match between the client and counselor's beliefs and values, type of therapy, and counselor openness to spiritual issues may be key factors that influence what clients want to talk about in counseling. It is our hope that clinicians find this review to be helpful in addressing the spiritual concerns of clients-whether religious, spiritual, or secular.