Transition metal dichalcogenides have been widely researched as promising heterogeneous materials to substitute the archetypal platinum noble metal electrocatalyst in electrochemical hydrogen production reaction. Considering the escalating interest in the development of transition metal dichalcogenides for hydrogen evolution reaction (HER), and the well-established vulnerability of Pt HER electrocatalyst towards sulfur poisoning, we are inspired to examine the impacts of poisoning by sulfur on both emergent and current electrocatalysts. A comparative investigation into the effects of sulfur poisoning on MoS₂ and Pt/C revealed that, contrary to initial expectations, MoS₂ is not completely invulnerable to poisoning. Moreover, with the use of X-ray photoelectron spectroscopy, correlations between the atomic percentages of Pt–S bonds and normalized Tafel slope and potential at –10 mA cm^–2 have also been determined. This study is imperative for the assessment of functionality of various materials for potential hydrogen evolution catalysis.