Chlorinated paraffins (CPs) are industrial products produced and used in bulk for various purposes. However, the analysis of CPs is challenging, as they are complex mixtures of compounds and isomers. This study develops an analytical method for the analysis of short-chain CPs (SCCPs) and medium-chain CPs (MCCPs) using gas chromatography coupled with quadrupole time-of-flight high‑resolution mass spectrometry operated in negative chemical ionization mode (GC‑NCI‑Q‑TOF‑HRMS). The linear relationship between chlorination and the CP total response factors was applied to quantify the CP content and the congener group distribution patterns. In a single injection, 24 SCCP formula groups and 24 MCCP formula groups were quantified. Extraction of accurate masses using TOF-HRMS allowed the SCCPs and MCCPs to be distinguished, with interference from other chemicals (for example, PCBs) being effectively avoided. The SCCP and MCCP detection limits were 24–81 ng/mL and 27–170 ng/mL, respectively. Comparison of the results with those obtained through gas chromatography coupled with low-resolution mass spectrometry operated under the same ionization mode (GC-NCI-LRMS) indicated that the developed technique was a more accurate and convenient method for the analysis of CPs in samples from a range of matrices.