Zinc sulfate heptahydrate, also known as white vitriol or zinc vitriol, is an inorganic compound with the molecular formula ZnSO4·7H2O. It forms colorless, rhombic crystal prisms and is a white crystalline powder, soluble in water and slightly soluble in ethanol. It loses water upon heating to 200°C and decomposes at 770°C.

Zinc sulfate heptahydrate is harmful if swallowed, causes severe eye damage, is toxic to aquatic life, and may have long-term adverse effects on water bodies. It is used as a mordant, wood preservative, paper industry bleaching agent, and in the production of artificial fibers, electrolysis, electroplating, pesticides, and zinc salts.