In this paper, a new analytical design technique for a three-section wideband Wilkinson power divider is presented. The proposed design technique utilizes the dual-frequency behavior of commensurate transmission lines for the even-mode analysis and contributes a set of completely new and rigorous design equations for the odd-mode analysis. Measurement of a fabricated prototype utilizing the proposed technique shows an excellent return-loss (>16 dB), insertion loss (<3.35 dB), and excellent isolation (>22.7 dB) over 104% fractional bandwidth extending beyond the minimum requirements.