A coating composition characterized by comprising an ingredient (A) which is a solution of a silicone oligomer having average structural units represented by R nSiOx/2(OH)y(OR )z (wherein R 's may be the same or different and each represents C1-3 alkyl, vinyl, or phenyl; R 's may be the same or different and each represents C1-3 alkyl; and 0.8 0, and z > 0, provided that y+z=4-n-x) and an ingredient (B) which is a buffered latent acid catalyst. The silicone oligomer solution is obtained by subjecting an alkoxysilane to hydrolysis and condensation polymerization. The coating composition containing the solution can form an organopolysiloxane film excellent especially in chemical durability such as resistance to water and boiling water.