The purpose of this review was to synthesize research on the effect of professional development (PD) targeting data-based decision-making processes on teachers' knowledge, skills, and self-efficacy related to curriculum-based measurement (CBM) and data-based decision-making (DBDM). To be eligible for this review, studies had to: (1) be published in English; (2) include in-service or pre-service K-12 teachers as participants; (3) use an empirical group design; and (4) include sufficient data to calculate an effect size for teacher outcome variables. The mean effect of DBDM PD on teacher outcomes was g = 0.57 (p < 0.001). This effect was not moderated by study quality. These results must be viewed through the lens of significant heterogeneity in effects across included studies, which could not be explained by follow-up sensitivity analyses. In addition, the experimental studies included in this review occurred under ideal, researcher-supported conditions, which impacts the generalizability of the effects of DBDM PD in practice. Implications for research and practice are discussed.