We propose an interfacial reaction model describing the kinetics of the synthesis of 1-phenoxyoctane from 1-bromooctane and sodium phenoxide in a nonionic microemulsion, In this model the microemulsion is divided into the aqueous and the organic subvolume. The interface is covered by a monolayer of surfactant molecules. The interfacial area is determined by the concentration of surfactant in the microemulsion. The reaction is assumed to take place only at the internal interface of the microemulsion. Due to the nanometer dimensions of the microemulsion droplets it is also assumed that there is no concentration gradient between the core of the droplets and the internal interface. Therefore, bulk concentrations of the reactants within the subvolumes are used for the kinetic evaluation of the obtained data. The model proves to be valid for the complete range of variations of the microemulsion composition studied here.