More and more, colleges and universities across the United States and throughout the world are relying on adjunct instructors (sometimes called casual academics or part time instructors) to teach classes in their field of expertise. Often, those classes require a blending of theory into practical application, such as in business, accounting and other career focused classes. Previous literature has shown that adjunct instructors often have little formal preparation for teaching, and even when some preparation is offered, it is often insufficient to establish confidence, or teaching self-efficacy, in the classroom. This study examined changes in teaching self-efficacy after adjunct instructors were provided information (articles) around constructivist teaching strategies within collaborative Community of Practice (CoP) meetings to discuss those strategies. The study was conducted at a small private college, which relied heavily on adjunct instructors to conduct classes. A quantitative pre-post survey, and qualitative comments throughout the intervention sessions were used to examine changes. Participants reported a significant increase in teaching self-efficacy, which was especially prominent amongst new instructors compared to those with more experience. There was also a self-reported increase in the use of more constructivist strategies within their classes over the course of the intervention. Finally, participants also rated the components of the intervention (articles and the CoP meetings) and while they rated them similarly in terms of impact, the CoP meetings were discussed as critical to both learning and application of strategies in practice. Future studies should examine how these strategies could be used in wider groups of instructors and how the effects might be enhanced if a longer program were used, but it is clear that providing opportunities for adjunct faculty to come together and discuss new strategies can help improve teaching self-efficacy in higher education.