Spinel MgFe 2 O 4 thin films are prepared with the spray pyrolysis technique. The morphological study shows sand-like crystallites on the film with porosity. The structural study substantiates the polycrystalline nature of the synthesised MgFe 2 O 4 films, which possess a spinel structure. The crystallite size is found to be 25-45 nm in size, which is noted from the morphological study. The energy dispersive X-ray analysis (EDAX) reveals the existence of iron, oxygen and magnesium in MgFe 2 O 4 film. The electrical resistance of MgFe 2 O 4 decreases rapidly when the film is exposed towards acetone and ethanol vapours. The synthesised MgFe 2 O 4 is highly sensitive to acetone vapour at 323 K. The selectivity, sensitivity, recovery time, stability and response time of MgFe 2 O 4 film to acetone and ethanol sensing are described in this article. The findings show that MgFe 2 O 4 films can be efficiently used for the detection of ethanol and acetone.