OBJECTIVE: Given the well-accepted health benefits, it is important to identify scalable ways to support people with long-term conditions (LTCs) to remain physically active. This systematic review aimed to evaluate the effect of digital tools on the maintenance of physical activity (PA) amongst this population. METHODS: Electronic databases were searched for randomised controlled trials investigating the effect of digital tools on PA maintenance at least three months post-intervention compared with a non-digital control in participants with long-term conditions. Meta-analyses were conducted at post-intervention and longest maintenance timepoint; subgroup analyses explored the effect of the type of control. Prospero registration: CRD42022299967. RESULTS: Twenty-three studies ( = 5350 participants) were included, with the majority at unclear/high risk of bias. Web-based tools were commonly used (18 studies), 10 monitored PA with a sensor, and digital interventions were often combined with supervised exercise/walks. The overall meta-analysis showed no significant difference in PA between digital interventions compared with any type of control (device-based outcomes: SMD = -0.07, 95% CI [-0.35, 0.21]; self-reported outcomes: SMD = 0.11, 95% CI [-0.01, 0.24]). However, this was moderated by type of control group with subgroup analyses suggesting that the effect of digital interventions on PA surpassed that of an inactive/minimal control at post-intervention (SMD = 0.29) and maintenance timepoints (SMD = 0.24). CONCLUSIONS: This review provides preliminary evidence that interventions incorporating digital tools may be more effective than minimal controls at supporting people with LTCs to maintain PA. Given the quality of the evidence, confidence in these findings is very low and may change with future research.