Intense competitive pressures have forced firms to go beyond their neighbourhoods to achieve competitive advantage. A feasible course of action for firms is embracing supply chain integration. However, there is concern on whether implementing supply chain integration results in enhanced firm performance. Hence, the major aim of this research was to investigate the link connecting supply chain integration implementation and performance of large manufacturing companies in Kenya. In particular, the study examined the link connecting supply chain integration, competitive advantage, environmental dynamism to firm performance. The study was anchored on four theories; resource-based view, resource dependence theory, systems theory and network theory. A cross-sectional descriptive research design was applied with primary data. The respondents of the study were persons overseeing supply chain functions in the sampled firms. From a sample size of 200 firms, 94 usable questionnaires were obtained resulting in a response proportion of 47%. The main data analysis method was partial least squares structural equation modelling (PLS-SEM). The study found that supply chain integration, competitive advantage and environmental dynamism had a significant combined effect on firm performance. The study affirms that the performance of manufacturing firms in Kenya can be strengthened by implementation of supply chain integration. This helps to settle the debate to some extent on whether it is fruitful for organizations to integrate their supply chain operations. These outcomes are also in congruence with resource-based perspective in the sense that integrating internal operations can be regarded as a rare, non-substitutable, valuable and imperfectly imitable resource. Moreover, the findings of the study are expected to provide directions to scholars on the How to cite this paper: Michael, C. K.