Polysorbate 20 (common commercial brand names include Kolliphor PS 20,[2] Scattics, Alkest TW 20, Tween 20, and Kotilen-20) is a polysorbate-type nonionic surfactant formed by the ethoxylation of sorbitan monolaurate.

Its stability and relative nontoxicity allows it to be used as a detergent and emulsifier in a number of domestic, scientific, and pharmacological applications.

As the name implies, the ethoxylation process leaves the molecule with 20 repeat units of polyethylene glycol; in practice these are distributed across 4 different chains, leading to a commercial product containing a range of chemical species.

The World Health Organization has suggested acceptable daily intake limits of 0–25 mg of polyoxyethylene sorbitan esters per kg body weight.

Polysorbate 20 has been used as a shape directing agent to synthesize spheroidal magnetite nanoassemblies.