This longitudinal study examined the contribution of morphological awareness to bilingual word learning of Malay-English bilingual children in Singapore where English is the medium of instruction. Participants took morphological awareness and lexical inference tasks in both English and Malay twice with an interval of about half a year, the first time at the end of Grade 3 (Time 1) and the second time at the end of the first semester of Grade 4 (Time 2). Structural equation modeling (SEM) analyses revealed that within both languages, morphological awareness significantly predicted lexical inference at Time 1 as well as Time 2, and the contribution also became strengthened over time. Cross-linguistic SEM analyses showed that concurrently at both Time 1 and Time 2, English morphological awareness only had a significant indirect effect on Malay lexical inference. The exact indirect relationships, however, varied between Time 1 and Time 2. In addition, an indirect effect of Time 1 English morphological awareness on Time 2 Malay lexical inference also surfaced. These findings suggest concurrent as well as longitudinal cross-linguistic transfer of morphological awareness from English to Malay.