The nematode family Anguinidae comprises mycophagous forms and individuals that infest plant bulbs, tubers, and aerial tissues. The Anguinae genus of gall-forming nematodes are obligate plant parasites. More than 40 generic species of the gall-forming Anguinidae have been described. Seed gall nematodes are of extraordinary and immense economic significance worldwide, and their various species affect all of the world’s most valuable crops. The seed gall nematodes, Anguina spp., prefer to inhabit the foliage of cereals and forage grasses. They engage in highly specialized interactions with plants and induce the development of a singular nutritional structure within the seeds of their hosts. Anguina species invade ovules, where they produce galls, deposit eggs, and reside as juveniles in the second life stage. This adolescent stage can persist as anhydrobiotes in the seed galls for several years. In numerous nations, Anguina tritici, Anguina agrostis, and Anguina funesta are economically significant agricultural and quarantine parasites. This chapter discusses morphological and molecular identification of the genus, its spread, dissemination, host diversity, detection, ecology, biological diversity in the environment, seed-borne aspects, symptoms, effects, and management.