Void fraction is an important parameter to design and simulate thermal systems involving two-phase flows. In this research, an experimental investigation of the void fraction in adiabatic two-phase flow of R1234yf in horizontal and smooth tubes with an internal diameter of 4.8 mm was carried out. For the experimental tests, the vapor quality ranges from 0.1 to 1 while two saturation temperatures (15 and 25°C) and two mass flow rates (180 and 280 kg.m − 2s−1) are investigated. The quick-closing valve(s) method is used to measure the volumetric void fraction. Tests are also undertaken with R134a used as a reference in this study. The results highlight that the void fraction of R1234yf is 5% lower than that for R134a. In addition, the experimental data of R1234yf were compared against seven correlations from the literature: the Baroczy and the Hughmark correlations were shown to provide the best prediction, with a mean absolute error of 2% and 3.2%, respectively.