Herd immunity through vaccination is a key measure to control COVID-19 pandemic. However, vaccine hesitancy remains a public health threat, which is still common among healthcare workers (HCWs). This systematic review aimed to synthesise evidence on HCWs' attitudes towards COVID-19 vaccination and analyse associated factors to provide information for vaccine policy development and practice. We searched PubMed, Embase, ScienceDirect, Web of Science and three Chinese databases for literature published on 12 February 2021. Two researchers screened the literature independently, and 13 studies were included in the systematic review. Vaccine acceptance varied widely and ranged from 27.7% to 77.3%. HCWs had positive attitudes towards future COVID-19 vaccines, while vaccine hesitancy was still common. Demographic variables such as men, older age and physicians were positive predictive factors. Women and nurses had more vaccine hesitancy. Previous influenza vaccination and self-perceived risk were facilitators. Concerns for safety, efficacy and effectiveness and distrust of the government were barriers. Influences of direct (COVID-19) patient care towards vaccination intention were less conclusive. Tailored communication strategies were needed to increase the uptake rate of COVID-19 vaccines among HCWs. More importantly, more data and information on the safety and efficacy of vaccines should be provided with transparency.