Thermosetting compositions which are excellent in storage stability, useful as one component thermosetting compositions, give cured products having excellent chemical properties, physical properties and weathering resistance and favorably utilized in coating compositions, ink, adhesive and molded plastics. The thermosetting compositions comprises a compound having in the molecule two or more hydroxyl groups and/or thiol groups blocked by a vinyl ether compound, a vinyl thioether compound or a heterocyclic compound having a vinyl type double bond and oxygen or sulfur as the hetero atom, a compound having two or more reactive functional groups which can form a chemical bond with the blocked hydroxyl and/or thiol compound by heating and a thermal latent acid catalyst. The blocked hydroxyl and/or thiol group of the first compound and the reactive functional group of the second compound may be comprised in the same molecule.