Studies on the effect of social media on political communication and participation have found that falsehood and promotion of agenda are common in Nigerian social media usage for political discussion. Some of Nigerian citizens are discouraged probably due to their belief that their votes may not count. The study therefore investigated the impact of social media on political discourse and public opinion before and during Nigeria's 2023 Election. The population of the study comprised 51 225 500 Facebook users in Nigeria. A convenience sample was used to select a sample of 500 participants for the study. Data was collected using a questionnaire through Qualtrics. Mean, Standard Deviation and Linear regression were used to analysed the data gathered for the study. The study found that social media has a high effect on political discourse, public opinion and political opinion during the Nigerian 2023 general elections. The study found that social media activeness has high impact on political expression opinions during Nigeria’s 2023 election; social media influenced political polarization and propaganda, but does not increase the spread of misinformation. The study concluded that electoral bodies and politicians must improve debate and public opinions through discussion of policies and ideologies to reduce polarization.