A dispersant or a dispersing agent is a substance, typically a  surfactant, that is added to a suspension of solid or liquid particles in a liquid (such as a colloid or emulsion) to improve the separation of the particles and to prevent their settling or clumping.
Dispersants are widely used to stabilize various industrial and artisanal products, such as paints, ferrofluids, and salad dressings. The plasticizers or superplasticizers, used to improve the workability of pastes like concrete and clay, are typically dispersants. The concept also largely overlaps with that of detergent, used to bring oily contamination into water suspension, and of emulsifier, used to create homogeneous mixtures of immiscible liquids like water and oil. Natural suspensions like milk and latex contain substances that act as dispersants.