It is widely argued that competition is no longer between organisations, but among supply chains. Effective Supply Chain Management (SCM) has become a potentially valuable way of securing competitive advantage and improving organisational performance. This paper conceptualises, develops and validates two dimensions of SCM practices (strategically managed BRs and internal manufacturing operations competence). The study is designed to identify the important factors that influence a firm's internal operations and involvement in supplier development, develop reliable and valid measures of these factors and test hypotheses on their interrelationships. Data for the study were collected from 245 companies in Thailand and the measurement scales were tested and validated using structural equation modelling. It is hoped that this study will provide an effective instrument for assessing the performance of the overall supply chain in Thailand.