The purpose of this research is to examine the relationship between trust in leader (cognitive-based trust, affective-based trust) and workplace relationships quality (leadermember exchange and coworker relationships). Data collected from 370 employees using a questionnaire at an educational sector in Mansoura University. The study adopts a positivism philosophy, a deductive approach, and a quantitative research method to discuss the research methodology. The study tests the hypotheses with Warp PLS version 6.The research findings show that trust in leader (cognitive-based trust and affective-based trust) has a significant positive impact on workplace relationship quality (leader-member exchange and coworker relationship). Furthermore, the contribution of this study is filling the literature review gap in human resource field.