An object of the invention is to provide a curable organic polymer having superior curability, a method for producing the same, and a curable composition containing the same. An organic polymer (A) including a silicon-containing organic group represented by the general formula (1):— SiR1aR2bXc  (1) (wherein, R1 that is present in the number of “a” each independently represents a group including a hydrocarbon group having 1 to 20 carbon atoms as a basic skeleton, in which at least one hydrogen atom on the carbon atoms of positions 1 to 3 is substituted with an electron-withdrawing group; R2 that is present in the number of “b” each independently represents a C1 to C20 hydrocarbon group, or a triorganosiloxy group represented by the formula of: (R′)3SiO— (wherein, R′ each independently represents a hydrocarbon group having 1 to 20 carbon atoms); X that is present in the number of “c” each independently represents a hydrolyzable group or a hydroxyl group; a is 1 or 2; b is 0 or 1; c is 1 or 2; and the relationship of: a+b+c=3 is satisfied) in the number of one or more on average per molecule, a method for producing the same, and a curable composition containing the same are provided.