The invention provides an aqueous coating composition, which can simplify storage of an anti-staining agent and is excellent not only in coating stability upon mixing the anti-staining agent with an emulsion resin coating and but also in anti-staining properties. Disclosed is an aqueous coating composition comprising, as essential components, a synthetic resin emulsion (A) having a pH value of 4.0 to 10.0 and a neutral silica sol (B) having a particle diameter of 1 to 200 nm and a pH value of 5.0 to less than 8.5, wherein the neutral silica sol (B) component is contained in an amount of 0.1 to 50 parts by weight in terms of solid content relative to 100 parts by weight of the solid content of the synthetic resin emulsion (A).