SignificanceJuvenile hormone (JH) intricately controls molting and metamorphosis in holometabolous insects.Ecdysone-induced protein 93F(E93) functions as an adult specifier gene in the pupal–adult transition. JH is known to repressE93expression to prevent immature larvae from bypassing the pupal stage and progressing to precocious adult development; however, the molecular mechanism underlying JH-mediatedE93repression remains unknown. Here, we demonstrated that JH-inducible Krüppel homolog 1 functions as a direct transcriptional repressor ofE93. This study markedly advances the present understanding of the molecular basis of JH function in repressing insect metamorphosis.