We report the first theoretical determination of cross sections and rate constants for the Si + OH -> SiO + H reaction based on dynamics calculations. Quasi-classical trajectory calculations have been carried out for several rotational states of OH using an ab initio potential energy surface recently developed for the X(2)A' ground electronic state of SiOH/HSiO. The cross sections behave with collision energies as expected for a barrierless reaction and are slightly sensitive to the rotational excitation of OH. The thermal rate constants evaluated over the range 10-1000 K show a marked temperature dependence below 200 K with a maximum value of 4.3 x 10(-10) cm(3) s(-1) at 20 K. (C) 2014 Elsevier B.V. All rights reserved.