The ORANGE (OR) protein regulates carotenoid accumulation and plastid development. Our work showed that OR is dually targeted to the nucleus and the chloroplasts. The expression level of Or regulates transcript abundances of genes for carotenoid and chlorophyll metabolism and accumulation in etiolated cotyledons. We demonstrated that OR physically interacts with a bHLH transcription factor, TCP14, which binds directly to promoter regions of its target genes, such as CAB4, ELIP1 and AtOr itself. OR-regulated gene expression relies on TCP14. Taken together, we proved that OR regulates etioplast development via its physical and genetic interactions with TCP14.