SPIRALS program was designed in accordance with the inclusive Universal Design for Learning approach and the social cognitive model of self-regulated learning. This project aims to promote cognitive, emotional, and behavioral engagement among elementary students, and especially those at high risk of dropping out (such as Roma students). To test the efficacy of the program, an intervention study was performed for four months within a truly inclusive learning environment, involving the whole classes. A quasi-experimental pre-test/post-test design with a control group (n = 63) and an experimental group (n = 57) was used. The dependent variables were student engagement (cognitive, emotional, and behavioral), academic self-concept, perceived climate of support, reading comprehension, and academic performance. Students in the experimental group exhibited statistically significant improvements compared to the control group in six of the seven dependent variables analyzed (behavioral and emotional engagement, academic self-concept, perceived climate of support, reading comprehension, and academic performance). Further, the magnitude of differences tended to be larger in student engagement, perceived climate of support, and reading comprehension than in academic self-concept or academic performance. These results provide evidence supporting the usefulness of intervention programs aimed at promoting student engagement, specifically among students at higher risk of failure or dropout.