Sodium Persulfate (Na2S2O8) or sodium persoxodisulfate is a chemical compound. It is a strong oxidizer. It is a severe irritant of skin, eyes, and respiratory system. It is almost non-hygroscopic and has particularly good ability to be stored for long time. It is easy and safe to handle. It is not combustible, but releases oxygen easily and assists combustion of other materials.

It is used as a bleach, both standalone (particularly in hair cosmetics) and as a detergent component. It is a replacement for ammonium persulfate in etching mixtures for zinc and printed circuit boards, and is used for pickling of copper and some other metals. It is a source of free radicals, making it useful as a radical initiator for emulsion polymerization reactions and for accelerated curing of low formaldehyde adhesives. It is also used as a soil conditioner and in manufacture of dyestuffs, modification of starch, bleach activator, desizing agent for oxidative desizing, etc.

Conditions/substances to avoid mixing persulfates with are: moisture, heat, flame, ignition sources, shock, friction, reducing agents, organic material, sodium peroxide, water, aluminium and powdered metals.

Sodium Persulfate is a oxidizing agent in chemistry, for example in a synthesis of diapocynin from apocynin where iron(II) sulfate is the radical initiator.