In this paper, the author describes the right to association as a fundamental human right closely related to the right to freedom of speech and expression of thought, and freedom of public assembly. Along with the analysis of domestic and international legislation that guarantees this right, the paper analyzes the provisions of the Law on Associations as a fundamental law in the Republic of Croatia related to the functioning of associations and the Law on Political Parties as a fundamental law in the Republic of Croatia related to the establishment of political parties. The central part of the paper deals with the topic of membership in political parties in the Republic of Croatia, and especially the termination of membership based on the disciplinary procedure. The determination of disciplinary responsibility points to statutory diversity in political parties, and the analysis also identifies certain contradictions and illogicalities in the determination of disciplinary responsibility. The paper points to such contradictions, especially the non-compliance with certain legal principles, and points to the need for more precise determination of the position of membership, their rights and obligations, implementation of disciplinary responsibility and termination of membership in the statutes of political parties.