<p>This study examines changes in the role of reading fluency for comprehension over the early years of reading acquisition and whether these developmental patterns differ across two distinct orthographies—English (alphabetic) and Chinese (morphosyllabic)—among bilingual children. Using both cross-sectional and longitudinal data from 631 English–Chinese bilingual children in Grades 1 to 4, we investigated the direct and indirect contributions of metalinguistic awareness (phonological and morphological), decoding fluency, and sentence reading fluency to reading comprehension in English and Chinese. Structural equation models revealed that in English, word reading fluency plays a significant role in early grades, but this diminishes over time, with sentence reading fluency emerging as a key mediator between decoding and comprehension in later grades. In contrast, Chinese reading comprehension in the early years was strongly predicted by character reading rather than word reading, while in the later grades word- and sentence-level fluency became more influential. Whereas the expected developmental pathway—from metalinguistic awareness to decoding, to sentence fluency, to comprehension—was observed in English, the Chinese models reflected a distinct trajectory in which character- and word-level processing served as the primary conduits to comprehension. Phonological awareness showed declining influence across age groups, whereas morphological awareness became a more robust predictor of text-level processing and comprehension, particularly in English. These findings underscore both universal and language-specific pathways in reading development and highlight the importance of tailoring reading instruction to the characteristics of each writing system and the developmental stage of the learners.</p>