STEM (Science, Technology, Engineering, and Mathematics) education is becoming an integral part of modern agricultural education. If the integration of STEM into agricultural education is to succeed, it is vital that educators feel confident in their ability to teach such material. This study examines Tennessee and Mississippi agricultural educators’ personal teaching efficacy and outcome expectancy levels towards STEM subjects and identifies factors that may play a role in the development of STEM teaching efficacy. Analysis indicated that educators felt most confident in their ability to teach science, followed by technology, mathematics and then engineering. Factors that influenced STEM personal teaching efficacy included the number of postsecondary STEM courses taken, gender, and CASE course completion. Regarding outcome expectancy, teachers felt similarly across the four STEM fields. The one factor found to influence STEM outcome expectancy included the number of postsecondary STEM courses taken. Recommendations for future research include exploring agricultural educators’ perceptions of engineering and its place in the agriculture industry, recognizing how engineering is taught at both the secondary and postsecondary level, understanding the experience of minorities in STEM, and identifying ways in which agricultural educators use technology in their classrooms. Recommendations for practice include offering preservice agricultural educators more engineering and technology courses, specifically highlighting how STEM concepts are used in the modern agricultural industry, and improving agricultural educator outcome expectancy levels.