This article meta-analytically reviews the research on the association between therapist positive regard (PR) and treatment outcome. The history of the construct of unconditional PR in client-centered theory and the efforts to clearly operationalize and measure this construct are reviewed. Several clinical examples are presented. The updated meta-analysis, which features expanded inclusion criteria and a larger number of studies (k = 64) than previous analyses, yielded a small positive association between PR and treatment outcome, g = .28. To control for the repeated use of data sets and study samples within the database, a multilevel meta-analysis was adopted that indicated a stronger relation between PR and clinical outcome (g = 0.36). These analyses support PR’s standing as a significant component of the therapy relationship that leads to improved clinical outcomes. The article concludes with limitations of the research, patient contributions, diversity considerations, and recommendations for using PR in practice.