The production of biobutanol is typically conducted via a fermentation method known as the acetone– butanol–ethanol (ABE) process, which produces three primary products: acetone, butanol, and ethanol. In the purification of ABE fermentation products, vapor–liquid equilibrium (VLE) data for the binary mixtures of these components are crucial for accurate process design and optimization. Therefore, isobaric VLE data for the binary mixtures of acetone + 1-butanol, acetone + ethanol, and ethanol + 1-butanol were investigated in this study. The VLE data were predicted using group-contribution activity coefficient models, specifically the UNIQUAC Functional-group Activity Coefficients (UNIFAC) and the modified UNIFAC (Dortmund) models. Minor discrepancies were observed between the calculated values and the experimental measurements for both models. Nevertheless, the modified UNIFAC (Dortmund) model exhibited slightly better agreement with the experimental data, as evidenced by lower deviations in the predicted values. The results indicate that both models are suitable for predicting the VLE behavior of binary mixtures relevant to ABE fermentation products.