Growth of layered NbSe2 has been carried out on a GaAs (111)B surface by molecular beam epitaxy (MBE). The optimum growth conditions to obtain high quality films were investigated by use of reflection high energy electron diffraction. Single crystalline films as thick as 100 nm were obtained when suitable surface treatment of the GaAs substrate was made with the interruption of the Nb beam or the use of a cracked Se beam. The factors determining the MBE growth of layered NbSe2 are also discussed.