This Special Issue contains 18 papers presented at the 10th International Conference on Multiphase Flow—ICMF2019. The papers are extended versions of a larger subset of conference contributions that were chosen from 130 manuscripts accepted by the ICMF2019 Scientific Committee for presentation at the conference. The selected manuscripts were then subjected to the usual, stringent peer-review process, by three referees, as done with any other manuscripts submitted to FTaC. Thus, the papers contained in this Issue are those which successfully passed a three-stage review and selection process.@en