This study reports the gas-phase homolytic P–H BDEs of a set of 30 phosphine-type oxides (i.e., R1R2P(=O)H) obtained using the W1w thermochemical protocol. We note that the P–H BDEs (at 298 K) of the species in this dataset differ by as much as 157.2 kJ mol–1, with (H2B)2P(=O)H having the lowest BDE (249.3 kJ mol–1) and F2P(=O)H having the highest (406.5 kJ mol–1). Furthermore, using the full set of 30 all-electron, non-relativistic, vibrationless bottom-of-the-well W1w P–H BDEs as reference values, we have identified several well-performing DFT methods that could be applied to the computation of the P–H BDEs of phosphine-type oxides. The best-performing DFTs (in conjunction with the A'VTZ basis set) were shown to be MN12-SX (MAD = 1.7 kJ mol–1) and MN12-L (MAD = 2.7 kJ mol–1).