This descriptive–analytic study was conducted to evaluate the level of chemical safety knowledge of three Iranian occupational groups including retailers of dangerous chemical substances, occupational health and safety (OH&S) professionals, and workers in chemical plants. The study also assessed their familiarity with the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) and old editions of US OSHA-HCS, Canadian WHMIS and UK CHIP. The current status of chemical labeling in Iran was also assessed. First, two questionnaires were compiled and validated. After determining the sample size, the questionnaires were filled out by 251 participants. A statistical test showed that a meaningful correlation exists between the age/education of the participants and their chemical safety knowledge and GHS familiarity scores (p < 0.05). However, no meaningful statistical correlation was observed between the type of occupation and awareness score. Analysis of the current status of chemical safety labeling revealed that the GHS diamond shape is not suitably familiar for Iranian chemical occupational groups. Further training is needed for proper reading and understanding of labels/catalogs, usage of safety data sheets (SDSs), and the meanings of warning labels in the Iranian chemical industry.