Learners' ability to infer unknown words' meanings (lexical inferencing) plays a key role in word knowledge development for second language (L2) learners. It has recently been acknowledged that learners' sensitivity to word-internal structures (morphological awareness) makes an important contribution to L2 lexical inferencing. However, it remains unclear whether the contribution of morphological awareness to lexical inferencing is affected by L2 learner-related factors (e.g., language skills). Data obtained from five paper-pencil tasks in Chinese for 73 L2 learners who studied Chinese for two semesters in China showed that (1) for more-skilled learners, morphological awareness significantly contributed to lexical inferencing with and without contextual cues, whereas no significant relationships existed between morphological awareness and lexical inferencing for less-skilled learners; and (2) L2 learners' morphological awareness does not equally facilitate lexical inferencing due to a possible threshold of linguistic knowledge. The findings have implications for learners' success in inferring the meanings of unknown words