Magnetic properties of the Al_1-xGa_xFeO₃ family of oxides crystallizing in a non-centro symmetric space group have been investigated in detail along with structural aspects by employing X-ray and neutron diffraction, M¨ossbauer spectroscopy and other techniques. The study has revealed the occurrence of several interesting features related to unit cell parameters, site disorder and ionic size. Using first-principles density functional theory based calculations, we have attempted to under stand how magnetic ordering and related properties in these oxides depend sensitively on disorder at the cation site. The origin and tendency of cations to disorder and the associated properties are traced to the local structure and ionic sizes.