Authentic assessment has emerged as a learner-centered approach that evaluates students' abilities through real-world tasks, practical applications, and meaningful problem-solving activities. Unlike traditional examinations that primarily measure memorization and recall, authentic assessment emphasizes higher-order thinking skills, creativity, collaboration, and the application of knowledge in realistic contexts. This study investigates the impact of authentic assessment on student learning, academic achievement, critical thinking, and learner engagement. A mixed-method research design involving 720 students, teachers, and educational administrators from secondary schools and higher education institutions was employed. Quantitative data were analyzed using descriptive statistics and regression analysis, while qualitative insights were gathered through interviews, classroom observations, and portfolio reviews. Findings indicate that authentic assessment significantly improves student motivation, knowledge retention, problem-solving abilities, and real-world competency development. The study concludes that integrating authentic assessment practices into educational systems can enhance learning quality and better prepare students for academic, professional, and societal challenges.