This intervention inquiry explored the impact of English morphological instruction on English and Malay morphological awareness evolution and word reading skills amid Malay–English bilingual fourth graders in Singapore, where English is the language of instruction. The intervention group experienced semester-long instruction in English derivation; the control group was taught with their regular English curriculum. Both groups were tested with derivational awareness and derived word decoding tasks in English and Malay at the end of Grade 3 prior to the intervention (pre-test) and at the end of the first semester of Grade 4 right after the intervention (post-test). There was no notable discrepancy between the two groups on all tasks at pre-testing. Notable intervention effects were found on English skill evolution in that the intervention group's performance gain was notably larger than that of the control group on all English tasks save the derived decoding fluency task. More important, such intervention effects were also clear with some Malay tasks. These findings offer empirical evidence that backs the advantages of morphological instruction to bilingual children's reading evolution and a potentially causal effect of cross-linguistic transfer of morphological awareness from English to Malay.