Abstract A model of symmetries and gauge interactions relating the electron and muon is considered. The model is based on the U L(1)⊗U R(1)⊗R L⊗R R group where U L(1)⊗U R(1) denotes the chiral e-μ rotation and R L⊗R R the chiral reflection of the electron field. The invariance under this group is spontaneously broken by the vacuum expectation values of scalar fields. A zeroth-order vacuum is found for which the zeroth-order electron mass vanishes, while one-loop corrections lead to a finite m e mμ ratio. The decay process μ → e + γ is strictly forbidden in this model.