The subject of the research is the ideology of social democracy and its applications in Sweden. As a matter of fact, every social democrat has his own personal answer to the question of what social democracy means. Social democracy is not, and never has been, a party with a fixed set of dogmas upon which every member must swear. It has a tradition of ideas shaped by more than a century of theoretical discussion and practical politics, and its development can be followed in party manifestos. Therefore, the subject of this research that includes Sweden, a Scandinavian state ruled by the Social Democratic Party for decades and the success story of social democracy there, which has transformed into a unique version of the achievements from central/local democratic administration to democratic economic prosperity and thus from long-term and high-level social peace to social justice and sustainable development, seems important as it is worth examining as a unique example that should always be explored. The research aims to examine the social democracy ideology and the success factors of this ideology, which has achieved success in the Scandinavian geography, through the case of Sweden. In this research, which mainly accepts the qualitative research methodology, the deductive approach is adopted, and the research is benefited from scientific research methods such as content and document analysis on 26 scientific documents, discourse analysis on 9 scientific documents, and hermeneutics as well. Within the scope of the literature review of the research, the basic scientific data and discourse sources are written documents, the sources used in the research are mostly recent scientific documents such as books, articles, reports (between 1990-2020), official publications of the Swedish Statistical Institute and the Swedish Social Democratic Party’s official party documents and publications between 1930-2000 are also scanned and examined. As the main results reached in this research are as follows; (a) it will be demonstrated that the Swedish Social Democratic Party has developed as a social movement in the country by and through the working class; (b) analyzes and determinations of the main factors and parameters of the Scandinavian success of the ideology of social democracy in Sweden will be described; (c) compared to other parties and movements in Sweden for decades, findings and determinations will be made as to why Swedish history is also related to the identity and special nature of the country's Social Democracy Party and the workers' movement. Anahtar Kelimeler: İsveç, Demokrasi, Sosyal Demokrasi, Sosyal Demokrasi Partisi