The article discusses the formation and development of political parties as a socio-political institution in the Republic of Belarus and the Republic of Poland. A comparative analysis of the legal regulation of the activities of political parties (in historical retrospect) and the formation of legal qualifications in the registration and activities of political parties are carried out. The chronological sequence considers the main stages of the improvement of legislation in relation to political parties both in one country and in another. Attention is paid to the legislative barriers to the activities of political parties and their role in the institutionalization of this socio-political institution.