Objective: A two-year longitudinal study examined the academic impact of the integration of ABCmouse Early Learning Academy, an online supplemental digital early learning resource, into prekindergarten and kindergarten. Design and Participants: With a naturalistic design, ABCmouse was provided to all 230 prekindergarten students enrolled in a district-run program for students identified as at risk for school failure. The following year, the prekindergarten sample entered kindergarten and were provided with ABCmouse along with their kindergarten peers (N = 571) within a quasi-experimental design. Half of the schools received regular access to the full ABCmouse curriculum for the entire school year, and half of the schools received limited access to literacy and full access to math activities for the first half of the year, and full access for the second half. Results: The students who completed more ABCmouse learning activities during the prekindergarten year scored higher on an assessment of kindergarten readiness skills than those who completed fewer activities. Across multiple kindergarten assessments, the results indicated that ABCmouse contributed to accelerated growth in literacy and math. Students who were less prepared at the start of the kindergarten year and completed more ABCmouse learning activities caught up to their peers. The number of ABCmouse learning activities completed over both school years was a strong predictor of literacy and math outcomes.