An analytically simple and efficient approach to the analysis of multiple wires in a rectangular cavity is developed. This approach addresses the coupling characterization of the multiple wires in terms currents induced on them by applying thin wire approximation. Electromagnetic sources exterior to the cavity excite at least one of the wires. The formulation of this problem makes use of the theory of Fourier series to approximate the waveform of unknown currents excited on each wire. The field distribution within the cavity is determined utilizing the orthogonality properties. Finally, a matrix equation for the unknown Fourier coefficients is obtained by enforcing appropriate boundary conditions on the axis of the wires. The interaction among the wires is taken into account. Selected numerical results are included to illustrate the effects of various conditions, namely, the load and the locations of the wires in the cavity.