Acesulfame potassium is a calorie-free artificial sweetener, also known as Acesulfame K or Ace K (K from Kalium, Latin for potassium), and marketed under the trade names Sunett and Sweet One. In the European Union it is also known under the E number (additive code) E950.

Acesulfame K is 180-200 times sweeter than sucrose (table sugar), as sweet as aspartame, about half as sweet as saccharin, and one-quarter the sweetness of sucralose. Like saccharin, it has a slightly bitter aftertaste, especially at high concentrations.