Gallium oxide (Ga2O3) having band-gap of about 4.9 eV is a promising material for optoelectronics. Ga2O3 single crystals homogeneously doped with transition metals and rare-earth elements during the growth process can be promising light-emitting materials. Nanoporous matrices fabricated on the Ga2O3 substrates, can be used to obtain nanowires and nanotubes of various materials which are promising structures for optoelectronics and photonics. High melting point (about 1740 C) and low vapor pressure cause difficulties of growth from liquid and vapor phase. The chemical vapor transport (CVT) in sealed ampoules can be more appropriate and simpler method for obtaining these crystals with controllable electrical parameters and impurity composition.  Present investigation is devoted to obtaining Ga2O3 crystals by CVT in the preliminary evacuated sealed quartz ampoules. The thermodynamic analysis of the composition of CVT systems with Ga2O3 and C, CO, CO+CO2, H2, HCl, HCl+H2, HBr, HI, Cl2, Br2, I2, S, P as transport agents (TAs) is carried out for wide temperature range and for various density/composition of TA. The influence of the growth temperature and of the TA density/composition on the mass transport rate is investigated theoretically and experimentally. Obtained results are compared with mass transport rate by physical vapor transport, and the possibility of increase in mass transport rate by several orders of magnitude at the presence of TAs is demonstrated. The TA compositions favorable for the growth of Ga2O3 films, for narrow prismatic crystals (Fig. 1(a)) and for wide crystals with the growth rate of about 1.5 mm per day (Fig. 1(b)) are found. Promising perspectives of some TAs for obtaining Ga2O3 crystals homogeneously doped during the growth process are analyzed.