The action of juvenile hormone (JH), vitally important for regulating physiological processes in insect development and reproduction, relies on the functionality of the juvenile hormone receptor (JHR). The essential ligand-binding component of JHR has been identified as the product of Methoprene-tolerant (Met) genes. Upon binding JH, the basic helix-loop-helix-PER-ARNT-SIM (bHLH-PAS) protein MET forms a transcriptionally active complex with another member of the same family to execute specific gene-expression programs. We will outline the basic molecular attributes of the signaling before discussing recent developments on the mode of JHR functioning at both the gene-regulatory and nongenomic levels. Structural and mechanistic features of JHR and an analogous ligand-regulated bHLH-PAS protein, aryl hydrocarbon receptor, will be compared with emphasis on agonist-induced protein interactions during the receptor activation and on ligand specificity and selectivity. While this chapter reflects substantial advances in JH research over the last two decades, undoubtedly, many additional complexities of JHR signaling are yet awaiting their discovery.