In this article, we adopt a grounded theory approach to examine the development of international market entry capabilities in start-ups. Using case studies and in-depth interviews from Finnish mobile communication technology start-ups, we find that market entry capabilities have two distinct subsets: entry-organizing and market intelligence capabilities. We discovered that trial-and-error and learning-by-doing mechanisms are the mechanisms through which capabilities are generated, deployed, and changed. Based on our observations, we build a preliminary model of factors influencing the development of capabilities. The article contributes to ongoing dialog in both the emergence of dynamic capabilities and the international entrepreneurship literatures.