Purpose: The paper aims to assess differences and similarities between e-commerce development in Czechia, Poland and Slovakia in the context of the EU’s Digital Single Market strategy. The theoretical framework of the paper is based on synthetic considerations related to the digital transformation and development of the EU digital economy. The DSM strategy identifies the barriers to e-commerce market development in the European space and sets directions for legal changes, creating favorable conditions for building a strong e-economy including e-commerce and a modern digital society in all EU member states. Design/methodology/approach: The empirical part of the paper presents differences in e-commerce development in three countries: Czechia, Poland and Slovakia. The research was based on the analysis of the literature and secondary sources. The former allowed for the identification of the consequences of the DSM strategy for the development of e-commerce in the EU member states, the latter allowed for a comparative assessment of e-commerce development in the three surveyed countries. The adopted research method allowed for the assessment of the size, structure and dynamics of the development of the e-commerce market in the three countries covered by the research. Findings: The presented analysis describes the status, conditions and development trends in e-commerce in Czechia, Poland and Slovakia. The three analyzed countries are – to a large degree – uniform in terms of cultural, historical and economic aspects. The development of e-commerce in these countries is similar, but it is also characterized by considerable differences. The similarities refer to the level of informatization, the socioeconomic characteristics of users and e-consumers, development projections until 2023, and the social acceptance of online shopping. Simultaneously, the analyzed countries have diversified industry structures of online markets, they differ in the values of ARPU indices and record considerably lower values of online shopping per capita as compared with average EU standards. Limitations in developing transborder trade are due to similar factors as in other EU member states. Research limitations/implications: The article, by its nature, has its limitations. They result from the concentration of considerations on the formal side of DSM – assessment of the DSM project architecture, its priorities and identification of opportunities and conditions of its implementation in each member country. The problem of diversifying e-commerce development in three countries is general and limited in the space of analysis. The limitations apply to the use of one research method, which is nonetheless important and adequate to the problem. When designing future research, we indicate the need to use methodological triangulation. An important and interesting direction of future research will be detailed studies of e-consumers, e-commerce strategies of enterprises and the extension of research to other countries, to the international environment. Originality/value: The presented comparative analysis is significant from the perspective of its cognitive value. It combines an approach of management sciences with the macro- and microeconomic perspective. The former represents a platform of corporate functioning and its development in the environment of networks, new business models and new consumer characteristics, behaviors and assessments of companies’ marketing offerings. The other perspective is expressed by a new macro- and microeconomic environment, the character of regulation, transborder online competitive mechanisms, continuous processes of digital transformation and e-economy development. The results of the research can lead to further research of corporate management and transborder strategies in the environment of the digital transformation and creation of the digital single market across Europe.