B ackground: Although the hospital inpatient setting arguably provides an ideal opportunity to engage patients in smoking cessation interventions, this is done infrequently. We therefore aimed to systematically review the perceived barriers to the implementation of smoking cessation interventions in the hospital inpatient setting. Methods: A systematic literature search was conducted specific to hospital-based healthcare workers' perceived barriers to implementing smoking cessation interventions. Reported barriers were categorised using the capability, opportunity and motivation (COM-B) framework. Results: Eighteen studies were selected for inclusion, which consisted of cross-sectional surveys and interviews. The most commonly identified barrier in capability was lack of knowledge (56% of studies); in Opportunity, it was a lack of time (78%); while in Motivation, a lack of perceived patient motivation to quit smoking (44%). Seventeen other barriers were also endorsed, but less frequently. Conclusion: Healthcare workers report a plethora of barriers to providing smoking cessation interventions in hospital settings, which cover all aspects of the COM-B framework. These impediments need to be addressed in a multidisciplinary approach, at clinical, educational, and administrative levels, to improve intervention provision.