The sensitivity of Ga-doped BN nanotubes to prevalent gas molecules (H2S, HS-, H2O2, and H2CO) has been studied using B3LYP density functional theory (DFT) method. The chemisorption of H2S, HS-, H2O2, and H2CO molecules on (8, 0) BN nanotubes are estimated to be -1.61, -4.05, -1.27, and -1.28 eV, respectively. The obtained results of binding energies imply that the Ga-doped (8, 0) BN nanotubes can be a promising candidate for modification of sensor materials for the detection of H2S, HS-, and H2CO molecules compared with the Ga-doped (5, 5) BN nanotubes. Also, these results represent that the Ga-doped (8, 0) BN nanotubes have high recovery time and high sensitivity to the presence of H2S, HS-, and H2CO molecules. (C) 2014 Elsevier B. V. All rights reserved.