The main goal of this paper is to show the level of globalization, its changes and the reasons of differentiation in highly developed countries. The advanced hypothesis states that a convergence process is taking place in the sphere of globalization. The research methods used were the following: historical, literature, descriptive analysis and statistical methods. Statistical data used in this paper come from KOF Globalization Index, and the World Bank Database. The research covered 16 countries of Western Europe, the USA, Canada, Japan, Australia and New Zealand. The time range of the research is 1990–2018. The conclusions of the study are as follows: highly developed countries are the most globalized. The level of globalization in individual countries varies, but the differences are not considerable. Medium-sized European countries are the most globalized, while non-European countries are the least globalized. The index of de jure globalization is much higher than the index of de facto globalization, especially in non-European countries. Starting from the 1990s, the level of globalization has increased significantly, although it has varied considerably. The highest increase was in the less globalized countries, the lowest in the most globalized ones. As a result, the differences between them have significantly decreased. Thus we can see the convergence in the sphere of globalization in highly developed countries. Differences in the level of globalization relate to land area, population number, population density, geographical location (distance from other highly developed countries) and participation in the integration process (countries that take part in it are virtually more globalized).