•A linear trajectory of Chinese vocabulary growth in grades one to three was charted.•Compounding, homograph, and radical awareness all predicted initial vocabulary.•Only homograph awareness predicted vocabulary growth in grades one to three.•Children with lower initial homograph awareness grew faster in vocabulary over time. The study examined the vocabulary growth trajectory and the relative contributions of three facets of morphological awareness (compounding, homograph, and radical awareness) in grade one to vocabulary levels and growth across grades one through three. We administered measures of morphological awareness that assessed lexical compounding, homograph, and semantic radical (in grade one) as well as vocabulary definition (two times in grade one, one time in grade two and three, respectively) to 204 Chinese native speakers. Latent growth modeling showed that vocabulary growth was linear with significant growth across grades. Individual differences were observed in initial vocabulary levels but not growth. All three facets of morphological awareness in grade one were significant predictors of initial vocabulary levels, whereas only homograph awareness predicted vocabulary growth. Specifically, homograph awareness had a negative slope where children with lower performance on homograph awareness in grade one exhibited larger growth in vocabulary scores. Theoretical and educational implications are discussed.