The subject of research in the paper is the impact of social networks on public sector marketing. Today, social networks are one of the most used media through which people and business entities daily transmit various information, communicate and improve the operations of business entities. Today, the public sector also uses social networks for marketing purposes in order to communicate with citizens, create a relationship with citizens, encourage citizens to participate in community events and be as transparent as possible in business. The aim of the paper is to show how social networks influence the marketing of the public sector based on the example of the local selfgovernment unit of the Municipality of Čepin. The Municipality of Čepin is present on three social networks as follows: Facebook, Instagram and Twitter, but is active only on two social networks, Facebook and Instagram. After conducting research on the marketing of the Municipality of Čepin on social networks, the importance of social networks today and the influence that social networks have on the marketing of the public sector have been confirmed. Also, it was learned that respondents believe that local self-government units should be present and active on social networks and that the implementation of marketing activities greatly contributes to the work and maintenance of relations between citizens and the Municipality of Čepin. Considering everything stated in the paper, it is concluded that the public sector, considering the growth of the influence of social networks, will not be half as successful in the future if it is not present and active on social networks and does not carry out marketing activities on them.