In recent years supply chain integration (SCI) has received increasing attention from scholars and practitioners. However, our knowledge of what influences the supply chain integration practice of relationship commitment is still very limited. The objective of this study is to investigate the relationship among supply chain justices (procedural, distributive and interactional), trust and inter-firms relationship commitment in mainland Pakistan. The research variables have considerable importance in the literature of supply chain management (SCM). The conceptual model comprises five hypotheses. Then hypotheses are tested via an empirical study in which data are collected from 170 manufacturers, distributors, suppliers and retailers of main stream spectrum industries in Pakistan. We used exploratory factor analysis (EFA), confirmatory factor analysis (CFA) to examine the validity and reliability of the measurement model, and structural equation modeling (SEM) to test the hypotheses. The findings delineate that supply chain justices can develop relationship commitment (affective and continuance) via establishing trust among supply chain partners. Moreover, this study reveals interesting and useful implications of supply chain justices, trust and relationship commitment for practitioners.