A new family of planthoppers, Szeiiniidae fam. nov., is described on the basis of a well-preserved forewing from the Upper Triassic Yanchang Formation of Huanglong County, Shaanxi Province, China. As the only specimen of the new family, Szeiinia huanglongensis gen. et sp. nov. differs from other families within Fulgoroidea by a unique combination of venation characters, and most significantly, the early branching of the MP vein, and low length/width ratio of the forewing. Our finding adds to the current understanding of morphological variability amongst planthoppers, and confirms high levels of diversity within Fulgoroidea at an early stage of the Mesozoic.