In this study, we investigated, using multiple modeling techniques, how the teaching self-efficacy of first-year alternative certification elementary and secondary teachers changed over the course of their first-year teaching and relations between that change and teachers' perceptions of formal supports. Using hierarchical linear modeling, we found that teachers' self-efficacy significantly increased over the course of the school year and that only one of our measures of support was positively and significantly related to change in self-efficacy. In particular, teachers' perceptions of school leader support covaried with change in their self-efficacy. Further, a structural equation model suggested that teachers' perceptions of school leader support were positively and significantly related to the magnitude of increase in self-efficacy. In other words, teachers who perceived greater support from their school leaders, had greater increases in their self-efficacy. We also analyzed data from interviews with a subset of the teachers to round out our understanding of the types of support from school leaders that first-year alternative certification teachers perceived as effective. Our full sample included 93 first-year teachers, 87 of whom completed the survey.