In this rapidly changing and technologically evolving world there is a need for skilled labor and professionals in the fields of science, technology, engineering, and mathematics (STEM). This warrants concern, as the number of individuals graduating from and/or pursuing careers in STEM fields is seriously lagging. Students must be inspired, be engaged, and have deep understandings of STEM content and their applications if they are to consider future studies and/or jobs in STEM fields. Integrative, inquiry-based STEM education is considered an effective approach for encouraging students in science and mathematics; however, teacher self-efficacy and teachers' beliefs about their abilities impact the implementation of inquiry-based practices in the classroom. We investigated the influence of a longitudinal STEM outreach program on science instruction and teachers' self-efficacy and beliefs. Findings suggested that although Grade 6, 7, and 8 teachers possessed confidence and heightened beliefs in their abilities to teach science and mathematics, interactive hands-on learning only occurred about half the time in their classrooms. Although participants agreed with the goals of STEM education, as well as expressed confidence in their ability to execute them, there was a disconnect between beliefs and implementation in practice. This study highlights the disparities that exist between self-perceptions of teaching in the STEM areas and those of a truly efficacious disposition.