Numerous reactions between sulfenyl chlorides and organic molecules proceed by way of radical reactions, in which homolytic cleavage of the S-Cl bond is a key step. Owing to the lack of data concerning the quantitative effect of substituents in governing the strength of S-Cl bonds toward homolytic cleavage, the present article reports an extensive dataset of gas-phase S-Cl bond dissociation enthalpies (BDEs) obtained using the high-level G4 thermochemical protocol. The BDEs of the species in this set range from 207.2 (ONSCl) to 279.7 kJ mol−1 (tBuSCl), with HSCl having a BDE of 267.6 kJ mol−1. In addition, the gas-phase S-Cl BDEs of six sulfonyl chlorides have also been reported, and these range from 267.2 kJ mol–1 (CF3SO2Cl) to 283.0 kJ mo1-1 (FSO2Cl).