Teacher awareness of STEM careers impacts students as they consider career choices. Researchers examined the effects of teacher professional development and lesson implementation in integrated science, technology, engineering, and math (STEM) on teacher awareness of STEM careers. Study subjects included high school science and engineering/technology teachers participating in a ten-day, 70-hour summer professional development institute designed by the funded project Teachers and Researchers Advancing Integrated Lessons in STEM (TRAILS) to educate teachers in adopting an integrated STEM education model incorporating a community of practice. The study used a quasi-experimental nonequivalent control group design that incorporated an experimental group and an untreated control group with both pretest, posttest, and delayed posttest assessments of non-randomized participants. Researchers analyzed changes in scores on the T-STEM survey of STEM career awareness using cumulative link mixed models (CLMM). STEM career awareness increased for teachers participating in professional development and the degree of change varied by group and assessment time.