OBJECTIVES: People experiencing severe mental illness (SMI) smoke at rates 2.5 times higher than the general population and have a reduced lifespan by 15-20 years, causing substantial health inequalities. This study examined how people with SMI resisted smoking cessation advice, delivered by primary care clinicians (general practitioners and nurses) during routine annual health reviews. METHODS: Using conversation analysis (CA), we analysed 56 audio-recorded consultations from a randomised controlled trial of annual health reviews in which smoking cessation advice was discussed. We identified a core collection of 21 instances of patient resistance and conducted detailed sequential analysis to examine how resistance to smoking cessation advice was expressed, and how clinicians responded. RESULTS: Analysis revealed two distinct patterns of resistance to smoking cessation advice: implicit rejection and explicit rejection. In implicit rejection sequences, patients foreground mental health concerns, thereby indicating that quitting cannot be acted upon at the moment. In explicit rejection sequences, patients rejected the advice with an explicit 'no' and expressed indifference to the health risks of smoking, presenting smoking as non-negotiable and making further discussion redundant. In both scenarios, clinicians responded with acknowledgements (e.g. "mm", "yeah", or "okay" indicating receipt and alignment), neither explicitly agreeing with the patient nor pushing back on their resistance. CONCLUSIONS: Addressing smoking-related health inequalities among people with SMI is challenging because quitting is often deprioritised in the context of competing mental health and social concerns. These difficulties are compounded by clinicians' challenges in raising and sustaining smoking cessation discussions. Recognising how resistance to quitting advice is interactionally produced can support more flexible and tailored cessation approaches that better align with patients' priorities. PRACTICE IMPLICATIONS: This study highlights the unique resistance sequence presented in consultations advising people with SMI to quit smoking. It provides implications for clinical professionals to adopt more responsive and tailored responses to the resistance.