Research has consistently linked social-emotional learning to important educational and life outcomes. Early elementary represents an opportune developmental period to proactively support children to acquire social-emotional skills that enable academic success. Using data from a large scale randomized controlled trial, the purpose of this study was to investigate the impact of the 4th edition of "Second Step" on early elementary students' academic-related outcomes. Participants were Kindergarten to 2nd grade students in 61 schools (310 teachers; 7,419 students) across six school districts in Washington State and Arizona. Multilevel models (Time × Condition) indicated the program had no positive main effect impact on academic outcomes. However, moderator analyses revealed that quality of implementation, specifically a measure of student engagement and dosage, was found to be associated with significant, albeit small, reading and classroom behavior outcomes. Findings from this study provide support for "Second Step" when implemented in the context of high engagement and higher dosage to have small but potentially meaningful collateral impact on early academic-related outcomes.