Abstract Epithelial morphogenesis generates complex tissue architectures with remarkable reproducibility, yet how tissue-scale epithelial curvature transitions are triggered in vivo remains poorly understood. Here, we show that epithelial morphogenesis during early pupal development of the Drosophila wing disc is regulated non-autonomously through spatially restricted remodeling of the basal extracellular matrix (ECM) by neighboring tissues. Live imaging analyses reveal a previously unrecognized