Introduction: There has been growing interest in recent decades in the effect of physical activity in older people as it was believed to play an important role in maintaining functional independence while reducing health care burden at a low cost. Recent reviews showed aerobic exercises were correlated with healthy ageing outcomes, however between- study variance and variation in study population and outcome measurements warrant a more comprehensive assessment of the current evidence. This scoping review of systematic reviews aimed to evaluate and synthesize review evidence on the effect of aerobic exercises on physical and mental well-being in older adults. Methods: Electronic databases, including Cochrane Database of Systematic Reviews, PubMed/MEDLINE, Embase, PsycINFO, CINAHL were searched from inception to 31 December 2018 to identify systematic reviews, with or without meta-analyses that examined the effectiveness of aerobic exercises in older adults. Methodological quality was assessed using Risk of Bias in Systematic reviews (ROBIS) tool. Results: Two hundred and thirteen reviews met the inclusion criteria. In this scoping review, we included 56 reviews that evaluated the effect of aerobic exercises: 24 examined the effect of aerobic exercises on physical outcomes, 26 examined mental outcomes, 5 examined both physical and mental outcomes and 2 examined the effect on quality of life (QoL). Most reviews showed positive effect of aerobic exercises on physical fitness (18 out of 23), mental well-being (15 out of 26) and quality of life (2 out of 2), while others showed inconsistent or negative results. Majority of the reviews reported low to moderate quality with moderate to high risk of bias. Conclusion: Overall, current evidence showed that aerobic exercises appear to be beneficial for physical fitness and QoL in elderly. The effectiveness of aerobic exercises to improve or maintain cognitive function is inconclusive hence would require further evidence prior to recommendation.