This multiple case study investigated the integration of science, technology, engineering, and mathematics (STEM) in three Florida high school agriculture programs. Observations, interviews, documents, and artifacts provided qualitative data that indicated the types of STEM knowledge taught. Variables of interest included student and teacher perceptions, teacher education, demographics, STEM integration, STEM knowledge, and student achievement and engagement. Each program taught students about a variety of STEM disciplines and careers. This study has added to the body of literature indicating student achievement in STEM can be increased by agricultural education. Science and technology were reliably integrated at high levels, but engineering and mathematics concepts were less consistently integrated across cases. Five case study propositions regarding the integration of STEM and the other variables of interest were accepted. Areas for further research within AG-STEM teacher education, teaching methods, and curriculum resources were suggested.