A polarizability decomposition model is proposed to quantitatively assess intramolecular charge transfer (CT) contributions to the polarizabilities of donor (D)-pi-acceptor (A) molecules. In this model, CT polarizability and its counterpart, local polarizability, are defined with explicit physical meanings. These two parts may contribute differently in magnitude and exhibit different structure dependences. Four typical D-p-A molecules are selected to rationalize their structure and solvent dependent polarizabilities in terms of CT partial contributions, which dominate the global polarizabilities and vary with D/A pair, conjugation path and solvent polarity. (C) 2011 Elsevier B.V. All rights reserved.