AimThe study assessed the knowledge, attitude, intentional practice and individualized factors of COVID‐19 vaccine uptake among adults in Tanzania.DesignHospital‐based analytical cross‐sectional study.MethodsQuantitative approaches were adopted to study 312 randomly selected adults using an interviewer‐administered structured questionnaire. Descriptive analysis established frequencies and percentages of variables at a 95% confidence interval and a 5% significance level.ResultsMean age was 24.66 ± 6.503 of which 61.5% were males. 86.9% of them were not vaccinated. 57.7% of respondents had inadequate knowledge about the COVID‐19 vaccine, and 61.5% had negative attitudes towards it. 63.8% of adults demonstrated an unwillingness to be vaccinated. Participants' sociodemographic characteristics profiles were significantly associated with COVID‐19 vaccine knowledge, attitude and willingness to uptake it (p < 0.05). Findings highlight the need for large‐scale interventions to address the low uptake vaccine. Adults' willingness to get a coronavirus vaccine was comparatively low. Sociodemographic profiles, knowledge and attitude were associated significantly with low uptake of the COVID‐19 vaccine among adults in Tanzania.