碳酸钾（化学式：K₂CO₃， 英文名：Potassium carbonate），呈无色结晶或白色颗粒，能吸湿，可溶于水。其溶液呈弱碱性。不溶于醇和醚。可由氢氧化钾与二氧化碳反应得到。

常用肥料草木灰中有碳酸钾。

Potassium carbonate (K₂CO₃) is a white salt, soluble in water (insoluble in ethanol) which forms a strongly alkaline solution. It can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It is deliquescent, often appearing a damp or wet solid. Potassium carbonate is used in the production of soap and glass.