Work-related asthma is highly prevalent and represents a significant societal and financial burden worldwide. This State of the Art series article explores the epidemiology, clinical features, diagnosis and management of occupational asthma (OA), which comprises sensitiser-induced asthma and irritant-induced asthma (IIA). Sensitiser-induced OA is the development of asthma through sensitisation to a substance in the workplace. OA is largely underdiagnosed, and its clinical manifestations are non-specific, which makes its diagnosis challenging. Early and accurate diagnosis of OA through comprehensive testing is primordial to avoid unwarranted removal from exposure and to allow early management of confirmed cases. Despite optimal management, up to 70% of patients with OA will have persistent asthma several years after diagnosis. IIA classically refers to the development of de novo asthma acutely following an intense exposure to an irritant agent. However, some cases of IIA following multiple high-level exposures or a chronic low-dose exposure have been reported.