This study modelled reading comprehension trajectories in Grades 4 to 6 English language learners (ELLs = 400), with different home language backgrounds, and in English monolinguals (EL1s = 153), and examined an augmented Simple View of Reading model. The contribution of Grade 1 (early) and Grade 4 (late) cognitive, language and word-level reading to Grade 6 reading comprehension was examined. The reading comprehension trajectory was non-linear in ELLs but linear in EL1s. Syntax predicted consistently rate of growth in reading comprehension. ELLs consistently underperformed EL1s on reading comprehension. Word-level reading and all components of language (vocabulary, syntax and listening comprehension) remained stable predictors of Grade 6 reading comprehension. Grade 1 phonological awareness, naming speed and working memory predicted reading comprehension in Grade 6, as did Grade 4 phonological short-term memory. Results support an augmented Simple View of Reading that includes cognitive, word-level and language components, and underscore the importance of considering developmental changes in the constructs.