Purpose:This systematic review and meta-analysis aimed to evaluate the effect of wearable devices for improving physical activity and health-related outcomes in cancer survivors.Methods:CINAHL,Cochrane,Ebscohost,MEDLINE,Pubmed,ProQuest Health and Medical Complete,ProQuest Nursing and Allied Health Source,ScienceDirect,and SPORTDiscus databases were searched for randomized controlled trials published before September 1,2020,that evaluated interventions involving wearable devices in cancer survivors.Standardized mean differences(SMDs)were calculated to assess effects on physical activity and health-related outcomes.Subgroup analyses were conducted to assess whether the effects differed by interventions and cancer characteristics.Risk of bias was assessed using the Cochrane risk of bias tool.Results:Thirty-five trials were included(breast cancer,n=15,43％).Intervention durations ranged between 4 weeks and 1 year.Most trials(n=25,71％)involved pedometer-based physical activity interventions.Seven(20％)involved Fitbit-based interventions,and 3(9％)involved other wearable physical activity trackers(e.g.,Polar,Garmin).Compared to usual care,wearable devices had moderate-to-large effects(SMD range 0.54-0.87,p＜0.001)on moderate-intensity physical activity,moderate-to-vigorous-intensity physical activity,total physical activity,and daily steps.Compared to usual care,those in the intervention had higher quality of life,aerobic fitness,physical function,and reduced fatigue(SMD range=0.18-0.66,allp＜0.05).Conclusion:Wearable physical activity trackers and pedometers are effective tools that increase physical activity and improve health-related out-comes in individuals with cancer.Identifying how these devices can be implemented for longer-term use with other intervention components remains an area for future research.