Cotton (Gossypium spp.) is one of the most economically important fiber crops worldwide, providing raw material for the textile industry. Upland cotton (G. hirsutum) accounts for about 90% of global production. Cotton fiber, a single elongated epidermal cell derived from the seed coat, undergoes a complex developmental process consisting of initiation, elongation, secondary cell wall thickening, and maturation. This process is regulated by intricate molecular networks involving various transcription factors (TFs) and metabolic pathways. Among these, MYB and HD-ZIP transcription factors play pivotal roles in epidermal cell differentiation, trichome and fiber initiation, and secondary wall biosynthesis. Carbohydrate and fatty acid metabolism contribute to fiber cell elongation and wall formation by supplying essential substrates and energy. Additionally, quantitative trait loci (QTLs) associated with fiber quality traits such as length and strength have been identified, offering valuable targets for genetic improvement. Understanding these regulatory mechanisms provides important insights for enhancing fiber yield and quality through molecular breeding and biotechnological approaches.