During the practicum, pre-service teachers (PSTs) practice instructional skills such as lesson planning and clarity of instruction. Different approaches to assisting PSTs with coaching, mentoring, or supervision have been developed to improve PSTs' instructional skills. We conducted a meta-analysis based on quasi-experimental and experimental studies. The results showed a small and significant overall effect of coaching, mentoring, or supervision on instructional skills (d = 0.41). Cooperating teachers' or supervisors' cognitive modeling (i.e., making cognitive processes explicit and demonstrating teaching-related practices) of lesson planning and teaching practices was a significant moderator (d = 0.90). Implications for initial teacher education are discussed.