The paper deals with Kant’s conception of harmony in its fundamental ontological meaning, i.e. in terms of that teleological harmony which was central for the dogmatic metaphysics and Kant will critically deconstruct and reconstruct not in a speculative-theoretical, but in a moral-teleological way. The basic arguments of this reconstruction are presented and discussed by examining the manner in which Kant re-elaborates the notion of the world as the unity of finite beings, conceivable only as a purposive harmony.