A few scattered examples of galls on plant fossils have been reported from the late Palacozoic and early Mesozoic. A more extensive record exists in the Cretaceous, largely coincident with the first radiation of angiosperms and the earliest fossil occurrences of several insect groups known today to induce gall formation. In the Tertiary a higher diversity of gall types are encountered. This review incorporates new data on morphological diversity in galls from several large assemblages of Cretaceous and early Tertiary angiosperm leaves. These fossil galls have also been compared with possible modern analogues. The implications of the new evidence are briefly considered in the context of the evolution of this important plant-arthropod interaction.