Many factors contribute to the achievement gap in the U.S. As an intervention to help narrow the gap, tutoring presents a potentially powerful solution. Decades of research suggest that tutoring is an effective, evidence-based approach to improve student success, with effect sizes ranging from 0.4. to 2.0. As many school systems in the U.S. move to online and hybrid environments, one-to-one online tutoring could be utilized to support student leaning. The purpose of this project was to explore the impact online tutoring had on student success as measured by Northwest Evaluation Association (NWEA) scores. Overall, online tutoring accounted for between 6% and 18% of the variability in NWEA math growth scores, depending on the number of tutoring hours received and how far behind a student was; the farther behind, the more hours of tutoring needed.