In the thesis, I address the opportunities for non-governmental organizations to cooperate with school. In the theoretical part I shed light on social change that fosters change in education. Current global, European and Slovenian guidelines for the education of children and adolescents are presented, as well as Slovenian legislation defining the contents of the primary school program and the possibilities for participation of external actors in the education process in the Slovenian primary school. I continue with definition of civil society, its organizations and the role of civil society in Slovenia. Finally, the cooperation of NGOs with public primary schools in different countries is presented. I discuss the benefits, risks and obstacles of cooperation and present guidelines for good cooperation between NGOs and the school. In the empirical part, I research the current practice of cooperation between Slovenian primary schools and non-governmental organizations. I was interested in what areas NGOs are getting involved in the school environment, what are the opportunities and barriers to cooperation and what are the expectations and outcomes of cooperation, as well as how cooperation between the school and NGOs could be improved. I was interested in the perspective of both parties involved. I used a combined quantitative and qualitative research approach consisting of two methods – online survey and semi-structured interview. Quantitative part included 72 professionals employed in Slovenian primary schools, the qualitative part included three representatives of primary schools and three representatives of non-governmental organizations operating in the field of violence and non-violent communication, drugs and addictions, global education and volunteering. In spite of the small sample, I have found that the opportunities for cooperation, on the one side, depend on the NGO itself, its subject matter, school visitors and source of funding, on the other side, they depend on the school, its staff, financial resources and the geographical location of the school, and on the third side, opportunities for cooperation depend on the state authorities, which define the contents of the primary school program, fund selected programs of NGOs and encourage cooperation between schools and NGOs operating in specific fields. Given that cooperation between NGOs and schools is less researched topic in Slovenia, the results of the research have highlighted the processes, attitudes and good practices in the field of NGO participation in educational processes in our country.