Following a pretest-posttest design with no control group, this paper evaluatesthe efficacy of an intervention program. Consisting of twelve sessions, theprogram endeavored to increase knowledge and use of self-regulated learningstrategies, as well as study time, in 277 first-year students in the Spanishsecondary education system. The intervention’s efficacy was assessedin terms of three variables: knowledge of self-regulated learning strategies,use of self-regulated learning strategies, and study time. The results ofpost-intervention data analysis indicate that statistically significant changesoccurred in students’ knowledge of self-regulated learning strategiesand weekly study time, but not in their use of self-regulated learningstrategies. When the sample was stratified into three groups (high, moderate,and low) according to baseline scores on the dependent variables, our findingsshow that students in the lower group profited most from the intervention on allthree variables. This suggests that participation in the program is especiallyuseful for at-risk students (i.e. those with little knowledge and use ofeffective learning strategies).