This research explores teachers' beliefs and practices regarding grammar instruction integrated into the Communicative Language Teaching (CLT) approach for English as a Foreign Language (EFL) learning in a vocational high school in Surakarta. This study aims to find out the relationship between teachers' beliefs and how they implement the strategy of grammar teaching integrated into Communicative Language Teaching, as well as the extent to which teachers' desired goals have been achieved. Using a qualitative case study method, the researcher collect the data through questionnaires, interviews, classroom observations, and document analysis involving two English teachers. The findings reveal that both teachers understood the principles of integrating grammar into CLT, emphasizing contextual applications of grammar in real-life communication. However, discrepancies in conceptual understanding, particularly about inductive teaching, indicate the need for targeted professional development. The study highlights a divergence in prioritizing accuracy and fluency. One teacher emphasized fluency to boost students' confidence, while the other aimed to balance fluency and accuracy for effective communication. Although lesson plans aligned with CLT principles, classroom practices revealed a stronger focus on grammar rules than on their functional application in real-life contexts. Delayed feedback and diverse evaluation methods fostered a supportive learning environment, yet the alignment between teachers' beliefs and classroom implementation requires further refinement. This research underscores the potential of CLT to enhance communicative competence and offers insights into improving grammar instruction strategies for EFL learning in vocational schools. However, it also highlights areas that require improvement, such as aligning theoretical understanding with practical application, balancing accuracy and fluency, and fostering a deeper focus on the functional use of grammar. The study provides recommendations for professional training, curriculum development, and future research to bridge the gap between theoretical understanding and practical application.