Leucocoprinus brebissonii is a species of fungus in the Agaricaceae family. It was first described by Louis-Luc Godey in 1874 as Lepiota brebissonii, and moved to Leucocoprinus by Marcel Locquin in 1943. It is commonly called the skullcap dapperling due to its distinctive pattern on the cap. Until recently, this mushroom was only found in Europe but over the last few years has been identified in the Pacific Northwest.