This study examines the effect of halal certification on consumer loyalty with consumer trust as a mediating variable in Banda Aceh City, an area known for its high level of compliance with Islamic values and the implementation of sharia. Although halal certification has become a standard requirement in product legitimacy, its effectiveness in building long-term consumer loyalty still depends heavily on the level of trust given by consumers to the certification process. The purpose of this study was to determine whether halal certification has a direct effect on consumer loyalty, and whether the relationship is mediated by consumer trust. This study uses a quantitative approach with an explanatory research design. Data were collected through structured questionnaires distributed to 150 Muslim consumers using a purposive sampling technique. Data analysis was conducted using SPSS through multiple regression and the Sobel test to test the mediation effect. The results showed that halal certification has a significant direct effect on consumer loyalty, as well as a significant indirect effect through consumer trust. The regression analysis showed that halal certification significantly increases consumer trust, which in turn contributes significantly to higher loyalty. The Sobel test confirmed the partial mediation role of trust in the relationship between halal certification and loyalty. These findings underscore the importance of trust as a psychological mechanism linking institutional credibility to consumer behavioral outcomes. This study concludes that halal certification alone is not enough to guarantee consumer loyalty unless supported by a consistent and transparent certification process that can build consumer trust. Therefore, business actors and certification institutions must not only comply with halal standards, but must also be able to communicate and maintain their credibility effectively to maintain consumer trust. Strengthening trust through ethical practices, education, and transparent halal processes can be a strategic approach in building sustainable consumer loyalty in the halal market.