Why do some entrepreneurial ecosystems thrive through global connection while others stagnate behind national borders? Banu Ozkazanc-Pan argues that ecosystems are not local formations but transnational - shaped by the movement of people, ideas, and identities across geographies and cultures. Drawing on transnational migration studies, she introduces a powerful new analytic framework built around transnational social fields, historical conjunctural analysis, and mobility methods. The framework centres on three scales of original research: in-depth interviews with eighteen globally mobile founders; a richly detailed case study of the Cambridge Innovation Center across five countries; and a geopolitically charged analysis of Taiwan's Asia Innovation Hub navigating the US-China technology rivalry. Timely and theoretically bold, Entrepreneurial Ecosystems confronts the shadow side of mobility - rising anti-immigration politics and immobility regimes - and asks whose voices shape entrepreneurship theory. Essential reading for scholars, policymakers, and practitioners seeking to understand innovation in a world on the move.