Purpose - The purpose of this paper is to examine this effect from the knowledge-based view (KBV). Design/methodology/approach - Data were collected from information technology (IT) firms in Taiwan. We contacted manufacturing managers to collect data. The questionnaires were distributed to 795 IT firms and 163 returned questionnaires were deemed usable. Findings-Furture, the findings the partial least squares (PLS) method indicate that learning relates positively to agility, which in turn relates positively to customization capability. In addition, learning relates positively to customization capability. Additionally, the mediating effect of agility on the relationship between learning and customization capability is significant. Research limitations/implications - Given the wide range of potential antecedents to agility and the limited theoretical and empirical research that has been conducted to date on factors that lead to agility, future research studies might widen their examination to include other potential factors. Further, the self-reported measures for all constructs were obtained from the manufacturing managers, which may increase the potential for common method bias. Future research studies that rely on top or middle managers as their sources could help clarify whether the results reported herein are informant-sensitive. Practical implications-Managers need to actively manage the human capital of their firms through a variety of organizational learning practices to stimulate the capability in managing agile manufacturing and forming customization capability. To facilitate the link between learning and favorable customization capability, managers need to recognize the importance of agility. They should utilize external and internal learning to cultivate a better level of customer agility, partnering agility, and operational agility, which in turn will result in better customization capability. Originality/value - This is one of the first studies to present a new conceptualization of the relationship between learning and agility, demonstrating how agility can be affected by learning. This study also fills the gap in the literature that calls for an empirical examination of the mediating effect of agility in the relationship between learning and customization capability.