A kinetic study on nucleophilic substitution reactions of 4-nitrophenyl X-substituted-benzoates (7a-i) with EtOK in anhydrous ethanol at $25.0{pm}0.1^{circ}C$ is reported. The plots of pseudo-first-order rate constants ($k_{obsd}$) vs. [EtOK] curve upward. Dissection of $k_{obsd}$ into the second-order rate constants for the reactions with the dissociated $EtO^-$ and ion-paired EtOK (i.e., $k_{EtO^-}$ and $k_{EtOK}$, respectively) has revealed that the ion-paired EtOK is more reactive than the dissociated $EtO^-$. Hammett plots for the reactions of 7a-i with the dissociated $EtO^-$ and ion-paired EtOK exhibit excellent linear correlations with ${ ho}_X$ = 3.00 and 2.47, respectively. The reactions have been suggested to proceed through a stepwise mechanism in which departure of the leaving-group occurs after the RDS. The correlation of the $k_{EtOK}/k_{EtO^-}$ ratio with the ${sigma}_X$ constants exhibits excellent linearity with a slope of -0.53. It is concluded that the ion-paired EtOK catalyzes the reaction by increasing the electrophilicity of the reaction center rather than by enhancing the nucleofugality of the leaving group.