This study examined the contributions of morphological awareness (MA) to second language (L2) word meaning inferencing in English-speaking adult learners of Chinese (N = 50). Three research questions were posed: Are L2 learners sensitive to the morphological structure of unknown multi-character words? Does first language (L1) MA contribute to L2 MA over and above L2 linguistic knowledge? Does L2 MA contribute to L2 word meaning inference over and above L1 MA and L2 linguistic knowledge? These questions were investigated through the use of a set of experimental and paper-and-pencil measurements of the aforementioned L1 and L2 reading subskills and L2 linguistic knowledge, as well as working memory. Several significant results were found. The L2 learners were sensitive to the morphological structure of multi-character words and more successful in guessing the meanings of novel words containing affixoids and familiar bases. L1 MA was found to transfer and facilitate the development of L2 MA over and above L2 linguistic knowledge. Additionally, L2 MA contributed to L2 word meaning inferencing indirectly through L2 linguistic knowledge. The discussion focuses on the intralingual and interlingual relationships among L1 MA, L2 MA, L2 linguistic knowledge, and L2 word meaning inferencing in adult L2 reading development.