The socio-emotional competencies of students are essential for supporting their school and personal performance. This article presents the results and analysis of an experiment with students from the National Polytechnic Institute (IPN, Mexico) and the subsequent application of an instrument to assess their socio-emotional competencies. The questions that guided the research were the following: (1) What is the level of development of the socio-emotional competencies of IPN students? (2) How do variables such as sex, age, and educational level affect the degree of development of socio-emotional competencies? (3) Are the socio-emotional competencies of the study group similar to those of the control group? These questions were examined through a quantitative analysis of the results of an instrument organized into nine theoretical dimensions with 72 questions that integrate the content of socio-emotional competencies. The instrument was applied to 405 students. The results show, first, a high level of development, on average, of the students’ socio-emotional competencies. Second, significant differences were found between the study group and the control group in two dimensions exclusively: empathy and autonomy. Similarly, the results show significant differences in the responses of men and women in two dimensions, regulation and pro-sociality, which, according to the analysis carried out, are related to prevailing gender stereotypes. A relevant conclusion is that the strengthening of socio-affective skills from school is essential for the comprehensive development of students. Failure to attend to them reproduces pre-existing conditions in families where poverty and violence do not allow for enriched socio-emotional environments.