In the information and knowledge society, technology and the COVID-19 pandemic have added to the debate on Media and Information Literacy (MIL). In Peru, in spite of the recommendations from international institutions, proper attention has not been given, generating gaps in the study curricula. From this perspective, the study investigates the level of development of MIL in students studying the last cycle of intermediate education. In order to determine this, the AMI-Peru-21 survey was designed and validated, based on the UNESCO proposals. This research is of a quantitative, descriptive and crosscurricular nature, which made it possible to diagnose the relationship of the socioformative factors with the levels of MIL achievement, based on a sample made up by 1250 students from the province of Arequipa. The results evidence the validity and reliability of the instrument ([alpha]=0.96) in order to measure the level of MIL, from the perspective of student self-perception, as well as the association of certain socioformative factors with MIL (p<0.000), among them, progress with age, i.e., older ages are associated with greater the levels of achievement, and females make more progress than males. It is also verified that access to basic services, such as electricity and the Internet, and the type of educational institution are correlated with higher levels of MIL achievement. From the evidence that is generated, in order to ensure the education of critical, ethical and responsible citizens, a set of initiatives is suggested to further the evolution of MIL in education.