Inocybe bongardii is an agaric fungus in the family Inocybaceae. It was originally described as a species of Agaricus by German botanist Johann Anton Weinmann in 1836. Lucien Quélet transferred it to the genus Inocybe in 1872. It is a common species with a widespread distribution. Fruit bodies grow on the ground, often in clay soils, and typically with broadleaf trees. The fruit bodies are suspected to be toxic, as they contain muscarine.