The demand for alternative gas sensor materials is increasing following the progress in the electronic industry. Complex ternary oxide materials have been emerging rapidly over 10 last years. Among ternary metal oxide compounds, the spinel ferrites are the most attractive materials due to structural and compositional versatility. This report will highlight the recent developments and will show the potential of the spinel ferrites on gas sensor technology. Sensing mechanisms for a range of gasses and humidity will be explained for n-type, p-type, mixed and substituted spinel ferrite gas sensors. The change in conduction mechanism will be discussed outlining electronic and chemical sensitization that both increase the gas response. This discussion surveys synthesis methods for producing spinel ferrites and discusses future prospects for further improvements.