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The agricultural green revolution spectacularly enhanced crop yield through modification of gibberellin (GA) signaling. However, in cotton, the GA signaling cascades remain elusive, limiting our potential to cultivate new cotton varieties and improve yield and quality. Here, we identified that GA prominently stimulated fiber elongation through the degradation of DELLA protein GhSLR1, thereby disabling GhSLR1's physical interaction with two transcription factors, GhZFP8 and GhBLH1. Subsequently, the resultant free GhBLH1 binds to GhKCS12 promoter and activates its expression to enhance VLCFAs biosynthesis. With a similar mechanism, the free GhZFP8 binds to GhSDCP1 promoter and activates its expression. As a result, GhSDCP1 upregulates the expression of GhPIF3 gene associated with plant cell elongation. Ultimately, the two parallel signaling cascades synergistically promote cotton fiber elongation. Our findings outline the mechanistic framework that translates the GA signal into fiber cell elongation, thereby offering a roadmap to improve cotton fiber quality and yield. [Display omitted] • Gibberellins promotes fiber cell elongation by degrading GhSLR1 • GhSLR1 interacts with two transcription factors, GhZFP8 and GhBLH1 • GhBLH1 activates the transcription of GhKCS12 and enhances VLCFA biosynthesis • GhZFP8 activates the expression of GhPIF3 by upregulating GhSDCP1 in cotton He et al. identified two signaling cascades, GhSLR1-GhZFP8- GhSDCP1 - GhPIF3 and GhSLR1-GhBLH1- GhKCS12 , which translate the gibberellins signal to regulate cotton fiber cell elongation. This finding can be potentially used in the field to improve cotton fiber quality. [ABSTRACT FROM AUTHOR]