The improvement or acquisition of socioemotional skills contributes to the academic and personal adaptation of university students. The way students think about themselves and others influence their social skills and well-being. Considering the importance of social competence for professional practice in the face of new social realities, the university must invest in programs that promote the socio-emotional development of students. This study compared the effects of interventions based on Rational Emotive Behavior Therapy and Psychoeducation on assertive skills and subjective well-being. This study involved 25 undergraduate students of a public university. The students were randomly allocated to three groups, including the Control group, and they were evaluated by means of questionnaires, inventories, scales, and written evaluation of the group process. The program consisted of 10 meetings and a 6-week follow-up. Irrational beliefs were reduced and their assertive skills' scores increased in the post-intervention and follow-up evaluations, regardless of the group. Only verbal reports from participants indicated an increase in well-being. The students' written reports after the end of the meetings indicate that the two forms of intervention were evaluated as promoting change by the students. One of the limitations of the study is the size of the groups. Despite the very small sample size, the study highlights that developing a set of flexible beliefs is fundamental to the exercise of assertiveness. (AU)