This paper presents an estimation of the magnitude of the school effect fo Colombia based on data from SERCE, the Segundo Estudio Regional Comparativo y Explicativo (Second Regional Comparative and Explanatory Survey).The sample consisted of 7,236 students of 3rd and 6th grades from 155 schools.For the analysis, multilevel models were adjusted to the following variables: socioeconomic index, cultural level, gender, nursery education, mother language, and mathematics and language scores.The results show an effect between 6% and 23%, greater for reading than for mathematics, as well as differences between schools related to the sociocultural and socioeconomic dissimilarities of students and schools.