SummaryBackgroundSleep and physical activity are inherent to human living, yet appear affected by Crohn's disease (CD), resulting in fatigue and disability.AimTo objectively assess sleep quality and physical activity and their associations using accelerometers, comparing CD vs. matched healthy control (HC) subjects.MethodsExactly 49 CD and 30 HC subjects completed surveys encompassing self‐reported fatigue and sleep quality, pathology testing and wore an accelerometer for 7 days, measuring physical activity and sleep. In this cross‐sectional observational study, per‐group comparisons were performed and in CD, factors associated with reduced activity and/or sleep quality were assessed via multivariate analyses.ResultsRegarding physical activity, CD subjects overall performed less total accelerometer counts (median 1.3 × 106 vs. 2.0 × 106), were more sedentary (97.7% vs. 96.2%) and completed fewer bouts of moderate‐vigorous intensity exercise (1.0 vs. 5.0, each P < 0.01 (Mann–Whitney) than HC over 7 days. Factors associated with poor physical activity in CD included elevated serum CRP (OR = 22.6), lower vitamin D3 (OR = 13.1) and longer disease duration (OR = 1.2 per year, each P < 0.05). Regarding sleep, the CD group had similar total sleep time (median 458 vs. 447 min, P = 0.56), but more awakenings post‐sleep onset (22 vs. 11, P = 0.01). Factors associated with severe sleep dysfunction in CD included lower haemoglobin (OR = 6.7) concurrent anti‐TNF (OR = 6.5, each P < 0.05) and opioid therapy (OR = 6.6, P = 0.09).ConclusionUtilising objective measurement in a habitual context over 7 days, patients with Crohn's disease exhibited poorer sleep quality and less physical activity than well‐matched healthy controls.