Provided are: a method for producing a metal oxide semiconductor film, which is capable of simply forming an oxide semiconductor film having high semiconductor characteristics at low temperatures and at atmospheric pressure with use of a low-cost material containing no indium that is a rare metal; a metal oxide semiconductor film; a thin film transistor; and an electronic device. This method for producing a metal oxide semiconductor film comprises: a metal oxide semiconductor precursor film formation step wherein a metal oxide semiconductor precursor film is formed by applying a solution, which contains zinc and tin serving as metal components and a solvent, to a substrate; and a conversion step wherein the metal oxide semiconductor precursor film is converted into a metal oxide semiconductor film by irradiating the metal oxide semiconductor precursor film with ultraviolet light, while heating the metal oxide semiconductor precursor film. Not less than 80% of all the metal components in the metal oxide semico
