The subject of the present disclosure is a composition for treating keratin fibers comprising, in a cosmetically acceptable medium, at least one oxidizing agent; at least one nonionic amphiphilic hydrophobic compound which is solid at ambient temperature; and, optionally, at least one hydrophilic surfactant; wherein the weight ratio of the at least one hydrophilic surfactant to the at least one nonionic amphiphilic hydrophobic compound ranges from 0:1 to 0.16:1, on the condition that when the at least one hydrophilic surfactant is present, it must be chosen from cationic and zwitterionic hydrophilic surfactants; and further wherein the composition is in the form of an aqueous dispersion.