Implementation planning is a consultative educator support strategy with preliminary evidence of effectiveness from single-case design research. This meta-analysis investigates the impacts of implementation planning on educator implementation and student outcomes and explores moderators of these relationships. Principles of open science and protections against publication bias are applied to encourage confidence, enhance transparency, and support reproducibility. Seven multiple-baseline studies, including published journal articles and unpublished dissertations, were identified using all possible combinations of the terms: (a) "implementation planning," "action planning," or "coping planning," and (b) "fidelity" or "integrity." Log response ratio effect sizes were calculated for each of the 31 included cases across all relevant dependent variables. A random effects meta- regression model was estimated for each dependent variable and moderator analyses were conducted to determine the impacts of implementer role, case type, intervention type, delivery modality, baseline type, and publication type. Results indicate that implementation planning had a significant effect on adherence and non-significant effects on quality, disruptive behavior, and academic engagement. Moderator analyses were significant for intervention type; implementation planning was more effective for behavior support plans than academic interventions or classroom management plans. Limitations and implications for open science research and school psychology practice are discussed. [This paper will be published in "School Psychology Review."]