In this letter, we study the optimum tradeoff between the spectral efficiency (SE) and energy efficiency (EE) for the two-user Gaussian interference channel (GIC). The achievable SE-EE tradeoff region of two-user GIC is obtained by studying the interactions between the two links due to their mutual interference. Each point in the SE-EE tradeoff region corresponds to a possible scheduling strategy between the two links. The optimum SE-EE tradeoff is then identified by maximizing the EE for a given sum SE, where the maximum EE is expressed as a closed-form function of the SE. The result analytically quantifies the impact of mutual interference on the SE-EE tradeoff. It is shown that the optimum scheduling strategy depends on the interference coefficients between the two links and the target SE.