Evidence regarding the impact of teachers' instructional development on student learning in higher education is scarce. In this study, we investigate the impact of an instructional development program for beginning university teachers on students' learning outcomes. We also explore whether this impact is dependent on class size and student level. Quantitative data were gathered from more than 1000 students at pre- and post-tests, using a quasi-experimental design. A multi-level analysis was conducted in which five models were estimated. The results show limited effects of teachers' instructional development. Several interpretations and perspectives for further research are discussed. (Contains 8 tables and 1 note.)