The degree of enforcement of political accountability at all levels of government affects the level of corruption. Active civil society shaping public opinion puts pressure on politicians to act responsibly and thus reduces the risk of corrupt practices. Increasing political responsibility is possible through the activities of non-governmental organizations (NGOs) as external actors in public policy. The aim of the study is to point out the possibilities of solving the problem of corruption through the anti-corruption NGOs in Slovakia. The research focuses on case studies of anti-corruption NGO activities focusing on mitigating levels of corruption. The selected NGOs are Against Corruption and Stop Corruption as two main civil society actors fighting corruption in Slovakia. The main method used is the case study method to map the complex activities of the two NGOs that support reducing the incidence of corruption.