This experimental database aimed to study the behavior of the air-water two-phase flow through thin orifice plates in a horizontal orientation. Two orifices with different area contraction ratios were tested. The database contains the raw pressure and dual impedance probe data in a fully instrumented test section. The test grid encompasses single- and two-phase flow. The superficial velocities of liquid varied from 0.20 m/s to 0.70 m/s, and gas varied from 0 m/s to 0.80 m/s.