<p>Successful readers of English must integrate their knowledge of word sounds (phonological awareness), meaning (morphosyntactic knowledge), and printed form (orthographic knowledge). Although various cognitive-linguistic skills are recognized as critical predictors of word reading, relatively little attention has been given to how these skills can be assessed online. To support English learners in various contexts, this study aimed to validate an online assessment battery for word reading and cognitive-linguistic skills, building on previous work examining their role in English word reading. Thus, our lab developed an online assessment battery including measures of silent word reading, invented spelling for phonological awareness, delayed copying to capture orthographic knowledge, and a novel morphological awareness task. We tested this English online assessment with Hong Kong Chinese children in grades 1–3 (<i>n</i> = 66), grades 4–6 (<i>n</i> = 52) and adult speakers (both native and non-native speakers) from the U.S. (<i>n</i> = 27). The results demonstrated that all cognitive-linguistic skills were generally moderately and significantly correlated with word reading across the three groups. The analysis showed that cognitive-linguistic skills explained 37% of the variance in word reading for grades 1–3, 47% for grades 4–6, and 47% for adult speakers. These results highlight the utility of these novel online assessments for explaining English word reading across learners and contexts.</p>