Potassium citrate (also known as tripotassium citrate) is a potassium salt of citric acid with the molecular formula K₃C₆H₅O₇. It is a white, hygroscopic crystalline powder. It is odorless with a saline taste. It contains 38.28% potassium by mass. In the monohydrate form it is highly hygroscopic and deliquescent.

As a food additive, potassium citrate is used to regulate acidity and is known as E number E332. Medicinally, it may be used to control kidney stones derived from either uric acid or cystine.

Potassium citrate is rapidly absorbed when given by mouth and is excreted in the urine. Since it is an alkaline salt it is effective in reducing the pain and frequency of urination when these are caused by highly acidic urine. It is used for this purpose in dogs and cats, but is chiefly employed as a non-irritating diuretic.

Potassium citrate is an effective way to treat/manage gout and arrhythmia,^{[medical citation needed]} if the patient is hypokalemic.

It is widely used to treat urinary calculi (kidney stones) and is often used by patients with cystinuria.^{[medical citation needed]} A study of 500 patients with recurrent stones found that it reduced the frequency of stones from 2 per year to a half per year.

It is also used as an alkanizing agent in the treatment of mild urinary tract infections such as cystitis. It is also used in many soft drinks as a buffering agent. Indeed, 2 l of crystal lite lemonade contains about 40 meqs; medical levels.^{[citation needed]}