Potassium trithiocarbonate is the inorganic compound with the chemical formula K2CS3.

It is the potassium salt of trithiocarbonic acid.

It consists of two potassium cations K+ and the trigonal planar trithiocarbonate dianion CS2−3.

It is a white solid, although impure samples often appear brown.

It is prepared by the reaction of potassium sulfide or potassium hydrosulfide with carbon disulfide.