The benefits and challenges of accessing international markets as a key strategy for many entrepreneurial ventures are well-known. But how can we effectively support startups’ expansion into foreign markets? This study takes an initial step to answer this question, arguing that entrepreneurial training can provide crucial experiential learning opportunities that foster startup internationalization. To empirically test our predictions, we explore a unique combination of proprietary application data from the German Accelerator (GA), a government-financed program that offers startups an international learning journey, and detailed startup- and founder-level information from Crunchbase and Revelio Labs, as well as qualitative evidence from a survey of GA alumni. We find that the average GA participant raises significantly more funding and hires more employees in the GA’s target countries, but not in their home markets, relative to a comparison group of startups that were admitted but did not attend for exogenous reasons. Quantitative and qualitative evidence suggests that in-person interactions in the target country are essential for eliciting these effects and that startups with limited prior international experience benefit most from participating in the program, both of which support our theoretical considerations about experiential learning.