According to Wallerstein's world system theory, which countries have the highest levels of economic development

The core countries

Explanation:

Wallerstein's world system theory categorizes countries into three categories: the core countries, the semi-periphery and the periphery.

The core countries are the rich countries, the most developed ones, with stronger governments, stronger armies, they tend to produce and export manufactured goods rather than raw materials.

These core countries include: Canada, USA, Australia, New Zealand, Japan and most of Western Europe (including UK and Scandinavia).