To obtain an org.-solvent-base thermosetting coating compsn. which can form a hard coating film excellent in stain resistance by compounding a thermosetting resin compsn. comprising a base resin and a crosslinker with colloidal silca.

This compsn. is prepd. by compounding a thermosetting resin compsn. comprising at least one base resin having crosslinking functional groups such as hydroxyl, epoxy, carboxyl, alkoxysilyl, or isocyanate groups and selected from among acrylic, vinyl, polyester, alkyd, and urethane resins and at least one crosslinker for crosslinking the base resin and selected from among melamine, urea, and guanamine resins, optionally blocked isocyanate compds., and carboxylated compds. with colloidal silca in an amt. of 10-140 wt.% (solid basis) of the resin solid of the compsn.