The article is devoted to the comparative legal analysis of the formation and development of the acquis communautaire in France, Germany and Switzerland with a view to identifying similarities and differences in the formation and development of the acquis communautaire in countries with different legal status in the European Union. The analysis was carried out using comparative legal, formal legal, dialectical, historical and legal, hermeneutical and other methods, as well as the principles of determinism, pluralism of opinions and complexity of knowledge. On the basis of and through the disclosure of the concept of “acquis communautaire”, the diversity of its understanding within different approaches and the nature of this phenomenon, as well as the study of the formation of the acquis communautaire specifics, it is established that this process took place in the course of formation of the European Communities in the 1950s with the participation of France and Germany on the basis of a combination of liberal market and general social values, and its development took place during the elaboration of the foundations of the mechanism for adoption of a common European policy. It is found that the patterns of formation and development of the acquis communautaire in France, Germany and Switzerland are overcoming contradictions and searching for compromises between France and Germany in all areas of common European policy and the need to coordinate their position with other members of the European Union. Furthermore, the similarity of these processes in France and Germany is rooted in their participation in the creation and development of the European Communities, in the formation of the acquis and its identical legal sources, and the difference lies in the motives and objectives of these States, their positions in certain areas of common European policy and procedural activities related to the implementation of the acquis into national legislation. At the same time, the article reveals that the specifics of formation and development of the European Union acquis in Switzerland are determined by its status as an associated country in the Union, which provides for the possibility of implementing the relevant acquis with certain exceptions on the basis of sectoral agreements between it and the European Union. The difference in the formation and development of the acquis between France and Germany, as well as Switzerland, is manifested in the mechanism and consequences of the implementation of the new acquis: Switzerland participates in the development process, but not in decision-making. Finally, it is noted that the common feature of the development of the EU acquis for all these countries is a combination of market-liberal and general social values and the introduction of a socially oriented market economy model.