BackgroundMimicry is an adaptive strategy widespread in modern ecosystems, yet its deep-time origins and evolution remain poorly understood due to the scarcity of unequivocal fossil evidence. Leaf mimicry has independently evolved in multiple insect lineages, reliable fossil evidence remains exceedingly rare and is primarily known from the Mesozoic and Cenozoic.ResultsWe report a highly specialised cicadomorphan forewing from the Guadalupian Yinping Formation of China (ca. 260 Ma) that exhibits a striking morphological resemblance to Sphenophyllum Brongniart, 1828, a groundcover widely distributed in late Paleozoic floras. An integrated assessment of wing morphology, geometric morphometric analysis, and the ecological association between the insect and the plant supports the hypothesis of mimicry.ConclusionsThis finding enriches the Paleozoic record of leaf mimicry in insects, broadens our understanding of its evolutionary history in Hemiptera, and provides a rare perspective on insect-plant ecological associations in the South China Block before the end-Permian mass extinction.