Despite the effectiveness of on-the-job training (OJT), few systematic empirical studies have been conducted on how OJT trainers instruct trainees in firms. The primary goal of this study was to investigate the characteristics of the trainer's instructional skills for OJT using survey data collected from 715 employees covering 22 firms. Results indicate that excellent OJT trainers use four types of instructional skills: (1) stretching trainee objectives, (2) monitoring their progress, (3) providing positive feedback, and (4) promoting reflection on results. The findings suggest that excellent OJT trainers facilitate trainees' experiential learning by promoting deliberate practice and reflective practice. Theoretical and managerial implications are also discussed.