A curable composition, comprising: 100 parts by weight of a reactive silyl group-containing organic polymer; and 0.1 to 20 parts by weight of a compound having 2 to 10 ethyloxy groups and no amino group, the organic polymer having at a molecular chain end a reactive silyl group represented by formula: -W-CH 2 -SiR 1 a R 2 b X c wherein R 1 is a C1-C20 hydrocarbon group in which at least one hydrogen atom on carbon atoms at positions 1 to 3 is replaced with a group selected from the group consisting of a halogen atom, -OR 3, -NR 4 R 5, -N=R 6, -SR 7, a C1-C20 perfluoroalkyl group, and a cyano group, wherein R 3, R 4, R 5, and R 7 are each a hydrogen atom or a C1-C20 monovalent substituted or unsubstituted hydrocarbon group, and R 6 is a C1-C20 divalent substituted or unsubstituted hydrocarbon group; R 2 is a C1-C20 hydrocarbon group, a C6-C20 aryl group, a C7-C20 aralkyl group, or a triorganosiloxy group represented by R 0 3 SiO- wherein the three R 0 's are C1-C20 hydrocarbon groups and may be the same as or different from each other; X is a hydroxy group or a hydrolyzable group; W is a linking group selected from the group consisting of-O-R 8 -, -O-CO-N(R 9)-, -N(R 9)-CO-O-, -N(R 9)-CO-N(R 9)-, -S-CO-NH-, and -NH-CO-S-, wherein R 8 is a C1-C8 divalent hydrocarbon group, and R 9 is hydrogen, an optionally halogen-substituted cyclic, linear, or branched C1-C18 alkyl or alkenyl group, or a C6-C18 aryl group; when W is-O-R 8 -, a is 1 or 2, b is 0 or 1, c is 1 or 2, and a + b + c = 3; when W is not -O-R 8 -, a is 0, 1, or 2, b is 0, 1 or 2, c is 1, 2, or 3, and a + b + c = 3; and each occurrence of R 1, R 2, X, W, or R 9 may be the same or different, the compound being a C1-C20 saturated hydrocarbon having one alkoxysilyl group, a C1-C20 hydrocarbon having two or more alkoxysilyl groups, or a C1-C20 polycarboxylic acid ester. 100 parts by weight of a reactive silyl group-containing organic polymer; and 0.1 to 20 parts by weight of a compound having 2 to 10 ethyloxy groups and no amino group, the organic polymer having at a molecular chain end a reactive silyl group represented by formula: -W-CH 2 -SiR 1 a R 2 b X c wherein R 1 is a C1-C20 hydrocarbon group in which at least one hydrogen atom on carbon atoms at positions 1 to 3 is replaced with a group selected from the group consisting of a halogen atom, -OR 3, -NR 4 R 5, -N=R 6, -SR 7, a C1-C20 perfluoroalkyl group, and a cyano group, wherein R 3, R 4, R 5, and R 7 are each a hydrogen atom or a C1-C20 monovalent substituted or unsubstituted hydrocarbon group, and R 6 is a C1-C20 divalent substituted or unsubstituted hydrocarbon group; R 2 is a C1-C20 hydrocarbon group, a C6-C20 aryl group, a C7-C20 aralkyl group, or a triorganosiloxy group represented by R 0 3 SiO- wherein the three R 0 's are C1-C20 hydrocarbon groups and may be the same as or different from each other; X is a hydroxy group or a hydrolyzable group; W is a linking group selected from the group consisting of-O-R 8 -, -O-CO-N(R 9)-, -N(R 9)-CO-O-, -N(R 9)-CO-N(R 9)-, -S-CO-NH-, and -NH-CO-S-, wherein R 8 is a C1-C8 divalent hydrocarbon group, and R 9 is hydrogen, an optionally halogen-substituted cyclic, linear, or branched C1-C18 alkyl or alkenyl group, or a C6-C18 aryl group; when W is-O-R 8 -, a is 1 or 2, b is 0 or 1, c is 1 or 2, and a + b + c = 3; when W is not -O-R 8 -, a is 0, 1, or 2, b is 0, 1 or 2, c is 1, 2, or 3, and a + b + c = 3; and each occurrence of R 1, R 2, X, W, or R 9 may be the same or different, the compound being a C1-C20 saturated hydrocarbon having one alkoxysilyl group, a C1-C20 hydrocarbon having two or more alkoxysilyl groups, or a C1-C20 polycarboxylic acid ester.