Field placements are arguably the most crucial component of traditional preservice special education teacher preparation. In field placements, cooperating teachers and university supervisors foster preservice special educators' sense of efficacy to teach, supporting their investment in continuing in the profession. Although ample research indicates the importance of cooperating teachers for preservice teachers' outcomes, little of this research has been conducted with preservice special educators. Moreover, prior research has almost never focused on university supervisors, despite their critical role bridging the relationship between content learned in coursework and the applied practice of special education within placement schools. In this investigation, we examined how preservice special educators' experiences of support from cooperating teachers and university supervisors relate to their teacher self-efficacy and their plans to teach. Analyzing a survey of 154 preservice special educators from six traditional preparation programs, we found that perceptions of university supervisors' support significantly predicted both self-efficacy and plans to teach, whereas perceptions of support from cooperating teachers were unrelated to either outcome. Our findings indicate that university supervisors' roles are crucial for preservice special educators' outcomes, and thus that they could be an important leverage point for improving special education teacher preparation. We call for much more extensive research on university supervisors' roles.