Sodium hypobromite is an inorganic compound with the chemical formula NaBrO. It is a sodium salt of hypobromous acid. It consists of sodium cations Na⁺ and hypobromite anions ⁻OBr. It is usually obtained as the pentahydrate, so the compound that is usually called sodium hypobromite actually has the formula NaOBr·5H₂O. It is a yellow-orange solid that is soluble in water. It adopts a monoclinic crystal structure with a Br–O bond length of 1.820 Å. It is the bromine analogue of sodium hypochlorite, the active ingredient in common bleach. In practice the salt is usually encountered as an aqueous solution.

Sodium hypobromite arises by treatment of aqueous solution of bromine with sodium hydroxide:

It can be prepared in situ for use as a reagent, such as in the synthesis of 3-aminopyridine from nicotinamide (via the Hofmann rearrangement).

Sodium hypobromite solutions must be prepared fresh since the compound slowly disproportionates to sodium bromide and sodium bromate: