The increasing prevalence of paediatric obesity and related metabolic complications has been mainly associated with lower aerobic fitness while less is known regarding potential musculoskeletal impairments. The purpose of the present systematic review was to report the evidence regarding muscular fitness in children and adolescents with obesity. A systematic article search was conducted between November 2014 and June 2015 using MEDLINE, EMBASE, CINAHL psycINFO, SPORTDiscus and SocINDEX. Articles published in English and reporting results on muscle strength and muscular fitness in children and adolescents aged 6 to 18 years were eligible. Of 548 identified titles, 36 studies were included for analyses. While laboratory-based studies described higher absolute muscular fitness in youth with obesity compared with their lean peers, these differences are negated when corrected for body weight and lean mass, then supporting field-based investigations. All interventional studies reviewed led to improved muscular fitness in youth with obesity. Children and adolescents with obesity display impaired muscular fitness compared to healthy-weight peers, which seems mainly due to factors such as excessive body weight and increased inertia of the body. Our analysis also points out the lack of information regarding the role of age, maturation or sex in the current literature and reveals that routinely used field tests analysing overall daily muscular fitness in children with obesity provide satisfactory results when compared to laboratory-based data.