Writing is a skill that has increased in significance for both researchers and classroom teachers due to changes in recent standards. Currently, many high school English Learners (ELs) are struggling to master this priority skill. A strategy that has been shown to be effective for adolescent writers is Self-Regulated Strategy Development (SRSD). Although this strategy has been researched, it has yet to be studied with EL high school students. However, the most effective method for providing feedback is not clear. This study sought to investigate the effectiveness of SRSD with vocabulary enhancement compared to business as usual comparison group on quality and accuracy measures for EL adolescents. This study used an experimental, randomized control design using both researcher created and standardized measures. Results indicated that students in the treatment group significantly improved over the business as usual control group on all quality measures. A small effect (g = 0.35) for accuracy (i.e., grammar, punctuation, sentence level errors) was found for proximal measures of grammar, punctuation, and reduction of sentence level errors using a researcher created measure. A moderator analysis also indicated there was a statistically significant interaction between the treatment grouping variable and receptive vocabulary on accuracy.