["Business Strategy and the Environment, EarlyView. ", "\nABSTRACT\nImproving environmental performance has become a strategic priority for manufacturing SMEs operating under resource and institutional constraints. Although prior research associates knowledge management practices (KMP) and entrepreneurial orientation (EO) with sustainability‐related outcomes, limited evidence explains how these capabilities interact to shape manufacturing‐level environmental performance, particularly in emerging economies. Using survey data from 363 Nigerian manufacturing SMEs and partial least squares structural equation modelling (PLS‐SEM), this study examines the relationships among KMP, EO and sustainable manufacturing performance (SMP). The findings show that KMP are positively associated with EO and SMP, whereas EO is strongly associated with SMP. EO also partially mediates the relationship between KMP and SMP, indicating that knowledge routines contribute more strongly to environmental performance when supported by entrepreneurial strategic behaviour. The study clarifies how EO functions as the capability mechanism linking KMP to manufacturing‐level environmental performance in resource‐constrained manufacturing SMEs.\n"]