Uptake of childhood vaccines is decreasing. While mandatory vaccination schemes can increase vaccine uptake rates, they can also cause backlash among some parents. We conducted a systematic review investigating parental beliefs about vaccine mandates and factors associated with support for mandatory vaccination schemes. We searched Embase, Ovid MEDLINE, Global Health, APA PsycINFO and Web of Science from inception to 17th September 2020. Seventeen studies (five qualitative, twelve quantitative) were eligible for inclusion. We synthesised results of qualitative and quantitative studies separately. As quantitative studies were heterogeneous in the mandatory vaccination schemes and associated factors investigated, there was no scope to conduct a meta-analysis. Instead, data were narratively synthesised, considering risk of bias ratings. Qualitative data were synthesised using meta-ethnography, synthesising themes reported across studies included. Quantitative studies reported that support for mandatory vaccination schemes was reasonably high (73% to 88%). However, due to heterogeneity, there was little evidence for any factors being consistently associated with support for mandatory vaccination. Qualitative studies gave an insight into how parents perceive mandatory vaccination. Studies found that parents perceived mandatory vaccination schemes as an infringement of their rights, and particularly disliked schemes offering financial incentives for vaccination. Nevertheless, some parents felt that schemes limiting access to schooling of unvaccinated children gave them “peace of mind.” Results should be taken with caution due to the purposive use of non-representative samples. Before deciding to mandate vaccination, it is important to understand the impact it could have on parental beliefs and attitudes about vaccination.