Onychomycosis is one of the most common nail diseases in adults but is described as infrequent in children. Data are, however, scattered and diverse. Studies have nevertheless suggested that the prevalence of onychomycosis is increasing in children lately and the aim of this review was therefore to examine this problem. Two authors individually searched PubMed, Embase, and Cochrane Library for articles on epidemiology and prevalence of onychomycosis in children. The literature search was conducted in accordance per PRISMA guidelines. In total 1042 articles were identified of which 23 were eligible for inclusion. One of the articles presented two studies and a total of 24 studies were therefore included. Seventeen studies presented data of the prevalence of onychomycosis in children in the general population and seven studies among children visiting a dermatological and pediatric department or clinic. The prevalence ranged from 0% to 7.66% with an overall discrete increase of 0.66% during the period 1972 to 2014 in population studies (not statistically significant). This review supports a trend towards an increased prevalence of onychomycosis in children, albeit based on a paucity of studies. The data suggests an increasing prevalence of onychomycosis with age, and co-infection with tinea pedis (reported in 25% of the studies). The most common pathogen reported was Trichophyton rubrum and onychomycosis was more prevalent in toenails compared to fingernails. The general characteristics of onychomycosis in children are thus similar to those described in adults.