We aimed to investigate the hesitancy and willingness of parents to vaccinate themselves and their children with a booster dose against severe acute respiratory syndrome coronavirus 2and related factors.We conducted a cross-sectional study in Puyang city, China. The information was collected, including demographic characteristics, willingness to receive a booster dose of coronavirus disease 2019(COVID-19) vaccine, and attitudes and concerns towardCOVID-19 and vaccines. Vaccine hesitancy was assessed in individuals completing the first two doses and booster eligible, while vaccine willingness was assessed in those completing the first two doses and not yet booster eligible.Among the participants completing two primary doses while not meeting the booster criteria, 95.4% (1465/1536) and 95.0% (1385/1458) had a willingness to a booster dose of COVID-19 vaccine for themselves and their children, respectively. Among the participants who met the booster criteria, 40.3% had vaccine hesitancy. Vaccine hesitancy and unwillingness tended to occur in people who were younger, less educated, less healthy, and with unsureness of vaccines' efficacy and adverse events (AE). The younger age of children, children in poorer health, and concern about the efficacy and AE of vaccines contributed to the participants' unwillingness to vaccinate their children.We observed a high willingness to the booster dose of COVID-19 vaccine both for the parents and their children, regardless of the eligibility to a booster dose. However, 40% of people had delayed vaccination behaviors. The promotion of scientific knowledge of vaccines' effectiveness and safety is needed, especially for people in poor health and parents with young children. Timely disclosure of AE caused by COVID-19 vaccines and proper aiding offered to people encountering AE are suggested.