PROBLEM TO BE SOLVED: To provide a surface-treated metal oxide particle which stably shows a high ultraviolet shielding property. Dispersions, compositions, and cosmetics containing such surface-treated metal oxide particles are provided. SOLUTION: The metal oxide particles are surface-treated with a silane coupling agent, and the metal oxide particles have a UV-shielding property, and the surface-treated metal oxide particles are 10% by mass and PEG-9. 10 parts by mass of a dispersion liquid containing 2% by mass of polydimethylsiloxyethyl dimethicone and 88% by mass of decamethylcyclopentasiloxane were mixed with 90 parts by mass of decamethylcyclopentasiloxane, and the mixture was used as a slide glass. Surface-treated metal oxide particles having a particle size of 15 μm or less when observed with an optical microscope. [Selection diagram] None【課題】安定的に高い紫外線遮蔽性を示す表面処理金属酸化物粒子を提供する。このような表面処理金属酸化物粒子を含む分散液、組成物、化粧料を提供する。【解決手段】シランカップリング剤で表面処理された金属酸化物粒子であって、金属酸化物粒子は紫外線遮蔽性を有し、表面処理された金属酸化物粒子を10質量%と、PEG-9ポリジメチルシロキシエチルジメチコンを2質量%と、デカメチルシクロペンタシロキサンを88質量%とからなる分散液を10質量部と、デカメチルシクロペンタシロキサン90質量部と、を混合し、その混合物をスライドガラスに挟んで、光学顕微鏡で観察したときに、観察される凝集物の粒子径が15μm以下である表面処理金属酸化物粒子。【選択図】なし