This study assessed the effects of the administration of a package of activities, known as Portfolio, on adolescents' cognitive functioning and self-regulation of learning. The study was carried out with a group of 109 students (mean age 15 years old) from the first level of Vocational Training. The students had learning difficulties, were unmotivated to study, and had behavior problems. A quasi-experimental pretest-posttest design was employed. The intervention involved group sessions in which certain, specially selected tasks from the psychopedagogic Instrumental Enrichment Program, the Philosophy for Children Program, and Project Intelligence were carried out. The intervention tasks were distributed over the entire school year. Statistically significant differences were observed between the experimental and the control groups on measures of general intelligence, cognitive flexibility, and metacognitive strategies (all p < .01). Statistically significant gains were observed for the experimental group on measures of decision making, problem solving, and self-regulation of learning (all p < .01).