International e-commerce is a strong global trend pushed by a tail wind of bolstering economic policies, changing customer behaviors, and improved logistics and technologies. This study investigates the reasons for performance variations among international e-commerce SMEs. Building on the capabilities perspective and market orientation literature, a research model is developed and tested with linear regression and mediation analysis on an effective sample of 99 Swedish SMEs which use e-commerce as an international sales channel. Our study shows that online marketing capabilities are necessary but not sufficient to increase performance among these companies. Our results show that marketing ambidexterity, reflected by both market-driven and market-driving approaches, is instrumental to leverage the effect of online marketing capabilities. © 2021 The Authors