BackgroundSedentary behaviour, which may have increased among GPs due to increasing use of telemedicine, is associated with many illnesses and increased all-cause mortality.AimTo explore levels of sedentary behaviour among GPs and General Practice Specialty Trainees (GPSTs).Design & settingSequential, cross-sectional design (initial online sedentary behaviour questionnaire, subsequent thigh-worn accelerometer sub-study) of GPs and GPSTs in Northern Ireland.MethodSelf-reported questionnaire data were aggregated and compared with device-measured accelerometry data.ResultsData from 353 participants (17.7% of GPs and GPSTs in Northern Ireland) revealed doctors in general practice self-reported higher workday sedentary time (10.33 (SD =2.97) hours) than those in secondary care (7.9 (SD =3.43) hours) (MD 2.43 hours; P<0.001). An active workstation (eg, sit-stand desk), was used by 5.6% of participants in general practice, while 86.0% of those without one would consider using one in future. Active workstation users self-reported lower workday sedentary time (7.88 (SD =3.2) hours) than non-users (10.47 (SD =2.88) hours) (MD –2.58 hours, P=0.001). Accelerometer sub-study participants underestimated their workday sedentary time by 0.17 hours (95% CI –1.86, 2.20; P=0.865), and non-workday sedentary time by 2.67 hours (95% CI 0.99, 4.35; P=0.003). Most GPs (80.7%) reported increased workday sitting time compared to prior to the COVID-19 pandemic, while 87.0% would prefer less workday sitting time.ConclusionGPs have high levels of workday sedentary time, which may be detrimental to their health. It is imperative to develop methods to address sedentary behaviour among GPs on workdays, both for their own health and the health of their patients.