The research is on the thrust to examine the influence of mass media on electoral victory of political parties in Osun State with a reference to four media houses and four political parties i.e Osun State Broadcasting Corporation, Gold 95.5 F.M, Ilesa, Osun Defender Newspaper and Nigerian Tribune Newspaper while the political parties include: All Progressive Congress (APC), People’ Democratic Party (PDP), Labour Party (LP) and Accord Party (AP). The study was anchored on Development Media Theory and Democratic Participant Theory. Survey research method was adopted in which 200 copies of questionnaires were administered and 180 were returned. Respondents were drawn using probability and non-probability technique. Also, the data were analysed and interpreted using table, frequency and percentage method. Most of the people in Osun state are affiliated to All Progress Congress and Peoples’ Democratic Party with majority of them participate in politics serving different roles as voters, party agents, pressmen, and election observers. It is recommended that journalist should try as much as they can to be fair in their news coverage so as to give equal coverage to all political parties.