(1 0 0) oriented BaNb2O6 films have been successfully grown on LaAlO3 (1 0 0) substrate at 750 degrees C or 450 degrees C in vacuum by pulsed laser deposition. The deposited BaNb2O6 PLD films exhibit room-temperature ferromagnetism. Ab initio calculations demonstrate that stoichiometric BaNb2O6 and that with barium vacancy are nonmagnetic, while oxygen and niobium vacancy can induce magnetism due to the spin-polarization of Nb s electrons and O p electrons respectively. Moreover, ferromagnetic coupling is energetically more favorable when two Nb/O vacancies are located third-nearest-neighbored. The observed room temperature ferromagnetism in BaNb2O6 films should be mainly induced by oxygen vacancies introduced during vacuum deposition, with certain contribution by Nb vacancies. (C) 2011 Elsevier B. V. All rights reserved.