School transitions are labeled as challenging events in students’ academic paths likely to affect students’ development and engagement in school negatively. Grounded on extant research advocating the need to act preventively, school-based mentoring programs emerge as responses suited to provide students with developmental and instructional support during school transitions. Using a multivariate mixed-effects model for repeated measures quasi-experimental design, the present study assessed the effectiveness of a 12-session group mentoring program designed to promote fifth-grade students’ self-regulation, school engagement, and goal setting during their first school transition. Participants were 330 fifth graders in four schools randomly assigned to treatment or control conditions. Students’ self-reported measures were collected in four moments. Data were analyzed using a multivariate mixed-effects model for repeated measures analyses with two covariates (age and gender) and considering the students’ level of prior mathematics knowledge. Results indicated that participating in the group mentoring program led to improvements in all dependent variables. The effect size found was large considering all dependent variables simultaneously. However, when considered individually, the effect sizes were medium, small, or null, depending on the dependent variable. Lastly, and contrary to expectations, the effectiveness of our program was not influenced by students’ level of prior mathematics knowledge. The relevance of group mentoring programs in addressing students’ engagement and self-regulation needs is discussed. Future research and educational implications for designing mentoring programs are provided.

学校过渡被认为是学生学业道路上的挑战性事件，可能会对学生的发展和在学校的参与产生负面影响。基于提倡采取预防措施的现有研究，基于学校的指导计划应运而生，适合在学校过渡期间为学生提供发展和教学支持。本研究使用多变量混合效应模型进行重复测量准实验设计，评估了为期 12 节的小组辅导计划的有效性，该计划旨在促进五年级学生在第一年的自我调节、学校参与和目标设定学校过渡。参与者是四所学校的 330 名五年级学生，随机分配到治疗组或对照组。学生的自我报告测量在四分钟内收集完毕。使用多元混合效应模型对数据进行分析，以两个协变量（年龄和性别）进行重复测量分析，并考虑学生的先前数学知识水平。结果表明，参与小组辅导计划导致所有因变量的改善。同时考虑所有因变量，发现的效应大小很大。然而，当单独考虑时，效应大小为中等、较小或为零，具体取决于因变量。最后，与预期相反，我们项目的有效性并未受到学生先前数学知识水平的影响。讨论了团体辅导计划在满足学生参与和自我调节需求方面的相关性。提供了设计指导计划的未来研究和教育意义。