Developing listening and speaking skills remains a major challenge in Vietnam’s exam-oriented English classrooms, where grammar and reading dominate instruction. This study proposes a quasi-experimental mixed-methods design to examine the effectiveness of Task-Based Language Teaching (TBLT) in improving these skills among 120 Grade 11 students over 12 weeks. The experimental group will receive TBLT instruction emphasizing authentic communication, while the control group follows the traditional presentation–practice–production (PPP) model. Data will be collected through pre- and post-tests, observations, questionnaires, and interviews, and analyzed using both quantitative and qualitative methods. It is expected that TBLT will significantly enhance students’ listening comprehension, speaking fluency, and motivation. The findings will contribute to the theoretical understanding of task-based pedagogy, provide practical insights for teachers in exam-driven contexts, and inform policy directions for communicative English curriculum reform in Vietnam.