This study took place in the context of schools collaborating with a local university to implement an evidence-based, 3-tiered model of prevention and supports targeting academic, behavioral, and social goals. We examined whether Self-Regulated Strategy Development (SRSD) instruction, delivered by grade 2 and 3 general education teachers to all students (Tier 1), would improve story or opinion essay writing among students with and without behavioral challenges, and whether differential effects existed. SRSD instruction was effective for both groups of students in terms of genre elements and quality. Students without challenging behaviors made greater gains than those with challenging behaviors on some outcome measures. Teachers implemented SRSD with fidelity; SRSD was viewed as socially valid by teachers and students. No results were found for academic engaged time or overall level of behavioral problems. Finally, students' cognitive capabilities were a weak and inconsistent predictor of SRSD writing gains. (Contains 7 tables and 1 note.)