Purpose: This paper aims to discuss the "truism" that learning organizations cannot be large organizations and, conversely, that large organizations cannot be learning organizations. This paper analyzes learning in the German and US armies in the Second World War, based on a four-dimensional model of the learning organization. Design/methodology/approach: The paper entails a secondary analysis of historical and military sources and data. Findings: It is found that the German and US armies differed in learning capacity, which can be plausibly, but not exclusively, related to differences in the battlefield performance between those armies in the Second World War. Research limitations/implications: The research scope of the paper is limited to the analysis of two particular armies in the Second World War. Implications of theory reside in the importance of organizational learning capacity and its dimensions for learning in current organizations. Practical implications: The paper has clear practical implications for large organizations wishing to become effective and responsible learning organizations. Originality/value: This is among the first organizational papers to analyze army learning in the Second World War and to derive lessons from that analysis for current large organizations.