Nickel(II) sulfate, or just nickel sulfate, usually refers to the inorganic compound with the formula NiSO4(H2O)6. This highly soluble blue green coloured salt is a common source of the Ni2+ ion for electroplating.

Approximately 40,000 tonnes were produced in 2005. It is mainly used for electroplating of nickel.

In 2005–2006, nickel sulfate was the top allergen in patch tests (19.0%).