To provide a method for producing a 4-substituted oxy-4'-hydroxydiphenylsulfone, which produces a 4-substituted oxy-4'-hydroxydiphenylsulfone useful as a raw material for a developer of thermosensitive recording material, a sensitizer, etc., under mild conditions in a short time in excellent selectively.

The method for producing a 4-substituted oxy-4'-hydroxydiphenylsulfone represented by general formula [2] (wherein R is a 1-8C alkyl group, a 2-8C alkenyl group or an aralkyl group which may contain a substituent group) comprises reacting 4,4'-dihydroxydiphenylsulfone with a halide represented by general formula [1]: R-X (wherein R is a 1-8C alkyl group, a 2-8C alkenyl group or an aralkyl group which may contain a substituent group, and X is a halogen) in an aqueous solvent in the presence of an alkali that is a mixture of at least two kinds of alkalis and contains 2-65 mol% of potassium hydroxide in the alkali mixture.