Potassium sulfite is the inorganic compound with the formula K2SO3.

It is the salt of potassium cation and sulfite anion.

Potassium sulfite is used for preserving food and beverages.

[4] Gilles-François Boulduc also discovered the salt in water of Passy in the 1720s.

The S-O distances are 1.515 Å, and the O-S-O angles are 105.2°[1]