Teacher self-efficacy and mentorship: Exploring the roles of Cooperating Teachers and University Supervisors in practicum experiences of preservice teachers

Preservice teachers' self-efficacy is central for professional development, yet evidence on how different mentors contribute to its development during practicum remains scarce. This study examined the relationship between Cooperating Teachers' and University Supervisors' mentorship and preservice teachers' self-efficacy after final practicum completion. Using a sequential mixed-methods design, 338 preservice teachers from 12 Chilean universities participated in the quantitative phase, and 12 with extreme self-efficacy levels were interviewed qualitatively. Modeling emerged as the main predictor of self-efficacy, with Cooperating Teachers influencing daily practice and University Supervisors contributing through pedagogical planning and reflective guidance. Qualitative data highlight complementary feedback, with Cooperating Teachers offering timely guidance and University Supervisors greater technical depth. Aligned with Bandura's (1986) self-efficacy sources theory, these results emphasise the importance of mentors' vicarious experiences and verbal persuasion, underscoring their complementary roles in teacher education and the need for stronger coordination to support effective transitions into teaching. • Modeling by CT and US significantly predicted teachers' self-efficacy. • CT feedback was valued for its immediacy, specificity, and formative tone. • US feedback enhanced reflection but sometimes lacked classroom connection. • High teacher self-efficacy linked to observing concrete modeling by CT. • Mentors played complementary roles that require stronger coordination.