The electrical resistivity of thin crystalline antimony films (thickness 8 and 27 nm) is investigated in the temperature range 1.6-300 K with magnetic fields up to 8 Tesla applied parallel to the film plane. The films were prepared by evaporation on cleaved (110) surfaces of GaAs substrates. Classical magnetoresistance is observed over the whole temperature range. Below approximately 6 K the resistivity exhibits a ln (T) increase which can be analyzed in terms of electron localization and electron-electron interaction theory. Accounting for the classical magnetoresistance the magnetic-field dependence of the resistance can be described with an appropriate theory leading to the characteristic length scales L(phi) and L(SO).