A room temperature-curing organopolysiloxane composition including (A) 100 parts by weight of at least one of two specific organopolysiloxanes; (B) 0.1 to 30 parts by weight of a silane compound having in its molecule an average of at least two Si-bonded hydrolyzable groups and in which the remaining Si-bonded group(s) is/are a group(s) selected from the group consisting of methyl, ethyl, propyl, vinyl and phenyl groups; a partial hydrolysis-condensation product thereof; or a mixture of these; and (C) 0.1 to 10 parts by weight of a mixture of siloxanes having degrees of polymerization of 2 to 10. The mixture of siloxanes is a partial hydrolysis-condensation product of a silane compound having a group selected from amino, epoxy, mercapto, acryloyl and methacryloyl groups each bonded to the silicon atom through a carbon atom and having a Si-bonded hydrolyzable group. The composition has superior adhesion to various resins.