The formation of secondary cell walls is tightly regulated spatio-temporally by various developmental and environmental signals. Successful fine-tuning of the trade-off between secondary cell wall biosynthesis and stress responses requires better understanding of how plant growth is regulated under environmental stress conditions. However, current understanding of the interplay between environmental signaling and secondary cell wall formation is limited. The lipid-derived plant hormone jasmonate (JA) and its derivatives are important signaling components involved in various physiological processes including plant growth, development, and abiotic/biotic stress response. Recent studies suggest that JA may be involved in secondary cell wall formation. We tested this hypothesis using the transcription factor MYB46, a master switch for secondary wall biosynthesis, and JA treatments. Both the transcripts and protein levels of MYB46 were significantly increased by the JA treatments, which also triggered the upregulation of MYB46 downstream genes with increased secondary wall formation. We then show that this JA-induced upregulation of MYB46 function was mediated by MYC2, a basic helix-loop-helix (bHLH) domain–containing transcription factor, which plays a pivotal role in the JA-mediated changes. We conclude that this MYC2-MYB46 module is a key component of the plant response to JA signaling.