An occupational hazard is a hazard experienced in the workplace. This encompasses many types of hazards, including chemical hazards, biological hazards (biohazards), psychosocial hazards, and physical hazards. In the United States, the National Institute for Occupational Safety and Health (NIOSH) conduct workplace investigations and research addressing workplace health and safety hazards resulting in guidelines. The Occupational Safety and Health Administration (OSHA) establishes enforceable standards to prevent workplace injuries and illnesses. In the EU, a similar role is taken by EU-OSHA.

Occupational hazard, as a term signifies both long-term and short-term risks associated with the workplace environment. It is a field of study within occupational safety and health and public health. Short term risks may include physical injury (e.g., eye, back, head, etc.,), while long-term risks may be an increased risk of developing occupational disease, such as cancer or heart disease. In general, adverse health effects caused by short term risks are reversible while those caused by long term risks are irreversible.