Prior research has investigated whether serial entrepreneurs effectively learn from one venture to the next. However, not all entrepreneurs demonstrate the same capacity for learning. A critical factor influencing entrepreneurial learning is individuals’ belief systems regarding the causes of outcomes in their experiences — whether they generally attribute success and failure to their own actions or to external factors such as the environment or luck. This distinction, known as Locus of Control (LOC), plays a pivotal role. Although LOC is one of the most extensively studied personality traits in psychology and is recognized as essential for learning, its specific impact on the learning process of serial entrepreneurs remains unexplored. Using longitudinal data from the NLSY79, we find that entrepreneurs with an internal LOC — those who believe they can influence outcomes through their own efforts — are more likely to learn effectively from prior entrepreneurial experiences. Furthermore, we find that an internal LOC is beneficial when past knowledge is less directly transferable, such as when entrepreneurs transition to a new industry, but its effect is insignificant for entrepreneurs who keep starting up in the same industry.