Cooperating teachers are often identified as some of the most important figures in the preparation of new teachers, and the reasons are not difficult to understand. Surprisingly, however, very little research has been conducted to quantify the effects of cooperating teachers on student teachers. This study examines the impact of student teachers' perceived interactions with their cooperating teachers and the influence that interaction has on student teachers' self‐efficacy for teaching. Results indicate a moderate correlation between perceptions of teaching efficacy and cooperating teacher‐student teacher interactions. Differences were found in the frequency of interaction based on the certification level of the student teacher, with elementary level student teachers perceiving a greater amount of interaction with their cooperating teachers. However, no differences based on certification level were detected in perceived efficacy. Student teachers' perceptions of the level of guidance offered by their cooperating teachers provided the most reliable predictor for their efficacy belief.