Objective: To evaluate the feasibility and acceptability of a theory-grounded, text message–based intervention targeting sedentary behaviour among university students. Design: Single-group repeated measures design. Setting: Post-secondary institution in British Columbia, Canada. Methods: Data concerning students’ sedentary behaviour were collected via online survey completed at three time points over the course of one university semester: baseline (T1), post-intervention (T2) and 2-week follow-up (T3). The 6-week intervention comprised four weekly text messages delivered to participants’ mobile devices. Participants’ attitudes regarding the intervention were evaluated together with other measures including constructs in the Health Action Process Approach (HAPA). Sedentary behaviour and physical activity were measured using the Physical Activity and Sedentary Behaviour Questionnaire (PASB-Q). Results: The intervention was generally well received by participants. Preliminary, observational data suggest some indices of user experience were statistically associated with behavioural outcomes and may inform future work. Hours per week of sedentary behaviour did not change across time points, whereas minutes per week of physical activity decreased significantly from baseline to follow-up. Conclusion: While study findings suggest minor modifications to the intervention may improve participants’ engagement, we demonstrated overall that a theory-grounded, text message–based intervention to reduce sedentary behaviour can be feasibly implemented. The efficacy of this intervention should be tested through a randomised control trial with a representative sample of the student population.