Research on blended learning's effect on student motivation has been largely limited to undergraduate and adult populations. To address this gap in research, a mixed methods approach is used to examine the impact of the STEM21 Academy's blended instructional approach on 9th-grade students' (1) engagement in science and mathematics learning; (2) acquisition of 21st century and inquiry skills; and (3) academic achievement in science. Additionally, the study examines the impact that blended instruction practices had on underserved students in particular. This study was completed within the context of a larger, longitudinal research study in 12 urban high schools in Connecticut and Massachusetts. As such, the examination is multifaceted and sits within a larger body of research that examines the affective and cognitive impact of blended instruction on students in grades 9-12. [This report was co-produced by Education Connection, one of Connecticut's six Regional Service Centers.]