The purpose of this study was to demonstrate the impact of a peer-tutoring program on academic performance among first-year students. The sample consisted of 102 first-year students from four-degree programs at a Spanish University. The academic performance was measured through the official student Academic reports. The assignment of the students to the experimental group (N = 51) and control group (N = 51) was done randomly. The intervention consisted of 20 highly structured individual weekly tutoring sessions delivered by senior and doctoral students, previously trained in three training sessions. The results show moderate effects' size and statistically significant differences in favor of the experimental group in the total academic course, as well as in the fall and spring semesters.