he lack of research in Indonesia on altruistic leadership and the role of trust in leaders as a mediating variable that examines the State Civil Apparatus makes this research interesting. The purpose of this study was to determine the effect of altruistic leadership on happiness in the workplace with trust in the leader as a mediating variable. This research is a type of quantitative research with a causality research design with the population is the State Civil Apparatus of District Indragiri Hilir Regency with a sample of 155 people. Data collection techniques using questionnaires and distribution using Google Forms. The data analysis tool in this study was Structural Equation Modeling (SEM) which was processed using SmartPLS 3.2.9 for data processing. The result of this study is that altruistic leadership has an effect on happiness in the workplace. Altruistic leadership has an effect on trust in the leader. Trust in leaders has an effect on happiness