The present invention has its object to provide a curable composition which has good curability and adhesiveness while containing an organotin-free catalyst. The present invention provides a one package curable composition which comprises (A) a polyoxyalkylene polymer having a silicon-containing group capable of crosslinking by forming a siloxane bond, (B) a (meth)acrylic ester polymer having a silicon-containing group capable of crosslinking by forming a siloxane bond and compatible with the component (A), and (C) (c1) a carboxylic acid of which the carbon atom adjacent to a carbonyl group is a quaternary carbon, and/or (c2) a metal carboxylate of which the carbon atom adjacent to a carbonyl group is a quaternary carbon.