This paper aims to present and discuss the execution of the Individualized Educational Plan (PEI, Portuguese initials), as an instrument in the schooling process of students with disabilities in the first stage of Elementary Education. To do so, we sought, through a qualitative approach, to conduct a study on the use of PEI in the process of school inclusion of students with intellectual disabilities (ID). It was found that the operationalization of the PEI does not occur to all students with ID in a direct way. However, considering the ID students’ educational needs, pedagogical adaptations are developed within the scope of the common classroom, mainly by the Specialized Pedagogical Assistant (SPA). On the other hand, the data collected demonstrated that, specifically, regarding the head teacher/regent there is a fragility of knowledge about special education and its specificities, which directly interferes in the promotion of schooling of the ID student inserted in the common school.