An organic-solvent dispersion containing fine polysilsesquioxane particles stably dispersed therein, which is obtained by adjusting the pH of an aqueous dispersion of fine polysilsesquioxane particles to 2 to 9, subsequently adding an organic solvent thereto, and then removing the water from the system; and an aqueous dispersion of fine polysilsesquioxane particles having an appropriate average particle diameter, which is obtained by adjusting the amount of a base catalyst to be used so as to be in a specific range. The process for producing an aqueous dispersion of fine polysilsesquioxane particles having a pH of 2 to 9 with an organic solvent. The process for producing an aqueous dispersion of fine polysilsesquioxane particles having an average particle diameter of 1 to 40 nm comprises mixing a dispersion stabilizer, a base catalyst, and trialkoxysilane in the presence of an aqueous solvent to produce an aqueous dispersion of fine polysilsesquioxane particles, and is characterized in that the base catalyst is used in an amount of 4 to 45 mmol/L per total amount of the aqueous solvent.