The dipole polarizabilities, second-order hyperpolarizabilities, and optical absorption spectra of MSi12 clusters (M = Sc-Zn) have been studied by using the (time-dependent) density functional theory. The results demonstrate that the correlation functional exerts more remarkable influence on the dipole polarizability and second-order hyperpolarizability calculations than the exchange term. Referring to MP2 results, B3LYP provides poorer dipole polarizabilities but more reliable second-order hyperpolarizabilities than B3PW91 and mPW1PW91 functionals. Additionally, the tunable (hyper)polarizabilities and optical absorption spectra have been evidently observed, which are attributed to the strong hybridization between 3d orbitals of M and 3s, 3p states of Si. (C) 2010 Elsevier B.V. All rights reserved.