Over 1.4 million high school students enroll in college-credit-bearing courses yearly, and 80% of that instruction occurs on secondary campuses under the tutelage of high school teachers (US Dept. of Education). Since First-Year Writing remains a common choice among enrollees, Concurrent Enrollment (CE) classrooms present a unique space for inquiry and collaboration into the quality and rigor of CE writing instruction. This study investigates CE writing instructors’ definitions of “rigor” in the college writing classroom and explores the training and support provided to CE writing instructors representing two- and four-year higher education institutions in Ohio. Findings suggest that on-going discipline-specific professional development can lead to definitions of rigor in high school writing spaces that align to postsecondary standards. This study also demonstrates that disparity exists in instructor preparation and support, especially in regard to discipline-specific training that could help close gaps in writing instruction.