Abstract
The speed at which firms internationalize has moved from a peripheral curiosity to a central construct in international business research, yet the literature remains fragmented across conceptual definitions, measurement traditions, and theoretical explanations. This review synthesizes 30 years of scholarship on internationalization speed by organizing the field around three questions: what speed is, what drives it, and what outcomes it generates. Drawing on temporal theory and the internationalization process literature, we first disentangle speed from the related but distinct constructs of earliness, degree, scope, pace, and rhythm and specify three analytically separable dimensions: entry speed, post-entry commitment speed, and expansion regularity. We then catalogue the measurement approaches employed in the empirical literature, showing that count-based and intensity-based ratios dominate despite well-documented issues of censoring, time compression, and functional-form sensitivity. Theoretically, we demonstrate that no single paradigm accounts for variation in speed; instead, the phenomenon is jointly shaped by firm capabilities, managerial cognition, network embeddedness, home-country institutions, and, increasingly, digital affordances that decouple international reach from physical resource commitments. Turning to performance outcomes, the evidence points to a predominantly curvilinear relationship between speed and performance, mediated by learning and legitimacy accumulation and moderated by absorptive capacity, entry mode, and institutional distance. We consolidate these insights into an integrative framework and propose a research agenda centred on temporal process designs, non-Western contexts, multilevel and configurational methods, sustainability outcomes, and measurement innovation. Our review suggests that speed is best understood not as a rate to be maximized but as a temporal capability whose performance consequences depend on the alignment between the pace of expansion and the pace at which the firm can absorb, integrate, and legitimize its acquired learning.