This chapter provides a systematic account of the causes of economic globalization. Within the global political economy (GPE) literature, economic globalization tends to be more precisely specified as ‘the emergence and operation of a single, worldwide economy’. This assists its measurement by reference to the intensity, extensity, and velocity of worldwide economic flows and interconnectedness, from trade, through production and finance, migration to information and data. Understood as a historical process, the concept of economic globalization also infers an evolving transformation or evolution in the organization and operation of the world economy. The chapter then reviews the principal theories of economic globalization, drawing upon the GPE literature. It develops a multi-theoretic account of economic globalization which captures its structural, conjunctural, and contingent causal factors. The chapter also demonstrates how this multi-theoretic framework is relevant to understanding the current crisis of economic globalization. It considers whether, in the aftermath of the Global Financial Crisis, this crisis is the precursor to a period of accelerating deglobalization.