This paper studies the effect of the integration of students with Special Educational Needs (SEN) on the academic achievement of their peers without SEN. This achievement is measured using performance in standardized reading and mathematics tests. The study also evaluates the effect of a policy that recognizes and increases resources for special educational needs that had not yet been considered and improves education provision protocols for students with SEN. Using administrative data and standardized test scores, we constructed a panel that follows a cohort of students before and after the reform, determining for each individual and year whether the class to which he/she belongs has any students with SEN. Our identification strategy employs panel data with fixed effects at the school, individual, and time levels. Estimates show that, on average, having a peer with SEN in the classroom has a negative effect on the academic performance of students without SEN. However, these effects are small and decrease, or even vanish, once better inclusion policies are in place. These results suggest that the effect on peers is almost totally canceled when more resources are provided and when adequate treatment and support protocols are implemented.