Artificial intelligence (AI) is increasingly associated with changes in e-commerce development, including demand generation, operational processes, and consumer interaction. The aim of the article is to examine and quantify the relationship between AI adoption and e-commerce development in 2023–2025 in an international context, with an emphasis on Ukraine’s position among European markets. The methodological framework of the study is a quantitative comparative analysis of data for Germany, France, Italy, Spain, Poland, the Netherlands, and Ukraine. An integral E-Commerce Index and an AI Adoption Index were created based on statistical sources, which were normalized in the range from 0 to 1. The hypothesis was tested by using correlation and regression analysis, as well as clustering of countries by a combination of e-commerce and AI maturity levels. Given the correlational design of the study, the findings are interpreted as evidence of statistical association rather than causation. The results show a persistent positive and statistically significant relationship between the AI adoption and the development of e-commerce levels. The leaders in terms of the AI Adoption Index are the Netherlands (0.88) and Germany (0.85), while Ukraine demonstrates the earliest phase of integration (0.25). The findings suggest that AI adoption is a significant correlate of e-commerce development rather than merely an auxiliary technological feature. The practical value of the results is the possibility of their use for building state policy of digital transformation and business strategies in the context of international competition.