Poor sleep is prevalent in inflammatory bowel disease [IBD] and is associated with increased symptom severity and decreased quality of life. To date, research is mostly cross-sectional, limiting the ability to examine the causal direction between sleep and IBD symptoms. This short report aims to assess the temporal associations among sleep quality, pain, fatigue, and physical activity in adults with IBD. Adult IBD patients [N = 18] completed a structured electronic diary two times per day [morning and evening] over 14 consecutive days. Morning diary items assessed sleep [sleep quality, wake after sleep onset, number of awakenings] and evening diary items assessed daytime IBD symptoms [abdominal pain, fatigue]. An actigraph measured daily step count [physical activity]. Generalised estimating equation models evaluated the lagged temporal associations between sleep ratings and next day pain, fatigue, and physical activity as well as reverse lagged temporal associations between daytime symptoms and physical activity and subsequent sleep ratings. Poor self-reported sleep quality predicted increased next day abdominal pain and fatigue scores. Increased time awake during the night predicted decreased next day physical activity. In the reverse analyses, only the relationship between daytime abdominal pain and wake after sleep onset was significant. Poor sleep appears to drive IBD-related outcomes, such as pain and fatigue. These findings are a first step in demonstrating the key role of sleep in the IBD patient experience, potentially resulting in a treatment target for intervention. Future research is needed to confirm results in a larger sample.