Background:Exercise is known to have many beneficial effects. Nevertheless, long-term adherence remains a challenge. A concept suggested to attend this problem is Exercise Booster Sessions (EBS). However, the current knowledge on EBS is limited. Objectives:This systematic review aimed to summarize and synthesize 1) the reported effects of EBS on physical function, pain, quality-of-life and societal costs and 2) delineate the basic components of EBS (frequency, intensity, type and time) following an exercise intervention in all clinical populations. Methods Seven databases (MEDLINE, EMBASE, CINAHL, SportDISCUS, Physiotherapy Evidence Database PEDro, Web of Science, and Cochrane Central Register of Controlled Trials) were electronically searched in August 2021. Included studies were randomized controlled trials (RCTs) of exercise interventions in all clinical populations followed by a period of EBS or a control group not receiving EBS. Results: Five studies on respectively knee osteoarthritis (n = 4) and low back pain (n = 1), reporting four different RCTs, were included. Four studies had a potential high risk of bias, whereas one was rated to have some concerns. One study found a positive effect of EBS on the Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, −46.0 (-80.0, −12.0), whereas the others did not find any differences. The frequency of EBS ranged from 0.09 − 1 session/week, and one study found EBS to be cost-effective. Conclusions: Current evidence suggests no or at best moderate effects of EBS on physical function and pain. However, the low number of trials, the potential risk of bias, plus the diversity in trial interventions prevent a firm conclusion.