Tulosesus impatiens (formerly Coprinellus impatiens) is a species of fungus in the family Psathyrellaceae. First described in 1821, it has been classified variously in the genera Psathyrella, Pseudocoprinus, Coprinarius, and Coprinus, before molecular phylogenetics reaffirmed it as a Coprinellus species in 2001. In 2020, German mycologists Dieter Wächter and Andreas Melzer reclassified many species of the Psathyrellaceae family based on a phylogenetic analysis and the species was renamed Tulosesus impatiens.

The fungus is found in North America and Europe, where the mushrooms grow on the ground in deciduous forests. The fruit bodies have buff caps that are up to 4 cm (1.6 in) in diameter, held by slender whitish stems that can be up to 10 cm (3.9 in) tall. Several other Coprinopsis species that resemble T. impatiens may be distinguished by differences in appearance, habit, or spore morphology.