An aqueous silica dispersion containing silica particles dispersed in an aqueous medium is provided. The surfaces of the silica particles are treated with reacted aminosilane compound. The aqueous silica dispersion also contains anionic polymeric dispersing agent. The dispersion of the silica particles into an aqueous medium containing both anionic polymeric dispersing agent and aminosilane compound allows the preparation of aqueous silica dispersions at higher solids and/or low viscosities than aqueous silica dispersions that are prepared without either the anionic polymeric dispersing agent or the aminosilane compound. The aqueous silica dispersion is combinable with aqueous emulsion polymers to modify the physical or appearance properties of articles formed from the emulsion polymer.