This study reports on the effects of the Pathway Project, a professional development intervention aimed at supporting the academic language development of English Learners (ELs). Using a subset of data collected during a multi-site cluster randomized controlled trial involving nine middle and six high schools in an urban, low-income school district over 3 years, this study examines how the Pathway Project intervention impacted ELs' abilities to analyze literature, use academic words, and include commentary in their essays. A total of 103 English teachers were stratified by school and grade and randomly assigned to the intervention or control group. Each year, Pathway teachers participated in 46 hours of training and learned how to apply a cognitive strategies approach to literacy instruction in order to help students understand, interpret, and write analytical essays about themes in literature. Through a textual analysis of 300 randomly sampled pre- and 300 post-intervention essays collected from 1,640 mainstreamed secondary ELs (820 experimental and 820 control), this study examined the ways in which the intervention impacted the writing outcomes of secondary ELs. A univariate analysis of variance (ANOVA) of the students' literary analysis and the use of commentary in their essays with the number of years in the treatment condition as the independent variable revealed significant effects of the intervention on the afore-mentioned posttest measures, with students who received 2 years of the intervention outperforming those who received only 1 year of the intervention.