Liquid-phase esterification of propionic acid with isoamyl alcohol using Amberlyst 70 ion exchange resin as catalyst was studied. Batch isothermal experiments were performed at different acid to alcohol molar ratios (1:2, 1:1, and 2:1), reaction temperatures (353.15, 373.15, and 393.15 K), and catalyst loadings (8.0, 4.0, and 0.8 wt % of (kg of cat)·(kg of soln)−1). Kinetic data were regressed with pseudohomogeneous and heterogeneous reaction models based upon mole fractions and nonrandom two-liquid (NRTL) computed activities. Obtained models accurately fit esterification kinetics and can be used in simulation of reaction and reactive distillation processes to produce isoamyl propionate.