The goal of this study was to evaluate the impact of IXL on early literacy development, as measured by the Star Early Literacy Assessment. Using a pretest-posttest design, we analyzed data from 2,959 kindergarten through 3rd-grade students in an Oklahoma school district during the 2021-22 school year. We found positive and statistically significant effects of IXL usage on both overall performance (i.e., Star Early Literacy scaled score) and literacy growth (i.e., Star Early Literacy student growth percentile), controlling for baseline performance and grade level. Specifically, students performed better on the assessment and showed greater early literacy growth when they answered more questions, reached proficiency in more skills, and/or spent more time on IXL.