This article synthesizes the roles of morphology in English reading acquisition and reports a meta-analytic structural equation modeling study (k = 107, N = 21,818) that tested the effects of morphological awareness (MA) on reading comprehension in school-aged readers. Moderator analysis was conducted through a set of subgroup comparisons based on readers' language status (monolingual vs. bilingual), age/grade (lower elementary, upper elementary, vs. middle/high school), and MA task modality (spoken vs. written). MA had significant indirect effects on reading comprehension via both word reading and vocabulary knowledge in the full sample as well as all subgroups. Its direct effect on reading comprehension, controlling for nonverbal reasoning, word reading, and vocabulary knowledge, was also significant in all subgroups except the lower elementary subgroup. Multi-group path analyses showed no significant subgroup difference in the magnitude of the direct effect of MA on reading comprehension for any moderator. However, two notable findings surfaced on the indirect effects of MA on reading comprehension: bilingual readers showed a smaller indirect effect of MA via word reading than did monolinguals; older readers showed a stronger indirect effect via vocabulary knowledge than did younger readers, whereas a converse pattern was found for the indirect effect via word reading. We conclude by pointing out the robust contribution of morphology to English reading comprehension and suggesting a strong meaning focus in morphological instruction, especially for bilingual and older school-aged readers.