Objective: The control of the COVID-19 pandemic can be successful with widespread acceptance of produced vaccines. To cover a wide range of people with vaccination, it is important to understand their behavioural perspectives. This study aims to investigate the knowledge and attitude of Iranian people towards the COVID-19 vaccines and its related factors.
Methods: This is a cross-sectional descriptive study. The study population includes all Iranian people who had access to social networks. The number of samples was determined using Cochran’s formula and the samples were recruited using a convenience sampling method in 2021 (n=370). A researcher-made questionnaire consisting of three sections of demographic information, knowledge and attitude was used to collect data. Data were analysed in SPSS v. 22 software using Kolmogorov-Smirnov, Spearman correlation, Kruskal-Wallis, and Mann-Whitney U tests. 
Results: The Mean±SD deviation of knowledge and attitude scores were 4.18±0.933 and 3.43±1.19, respectively. A strong positive correlation was observed between knowledge about and attitudes towards COVID-19 vaccines. There was a significant difference between the scores of knowledge and attitude based on age, gender, marital status, income level, history of infection to COVID-19, and the death of a loved one due to COVID-19.
Conclusion: The levels of knowledge and attitude towards the COVID-19 vaccines are high in Iran. Since the knowledge and attitude in young, female, single, and low-income level people are less than in older, male, married and high-income people, the necessary measures should be taken to increase their awareness and attitude through the various social networks available to them.