The achievement of positive learning outcomes is central to students' educational experience. Various important issues in students' learning outcomes are prevalent in the educational landscape. These issues encompass the significance of using valid and reliable assessments, the mounting pressure on accountability, the necessity for equal access to high-quality education, and the utilisation of technology. Additionally, there is a growing awareness of the importance of preparing students for the demands of the 21st-century workforce, which requires a broader range of competencies beyond traditional academic skills. It is essential to address these issues by continually focusing on and working together among educators, policymakers, and researchers to improve student learning outcomes. This article provides an overview of learning outcomes and the emergence of achievers and underachievers in educational settings. The first section defines learning outcomes and discusses the benefits of stating expected learning outcomes and guidelines for developing good statements. The article then explores the differences in cognitive functioning between achievers and underachievers, along with the classification and identification of these groups through a literature review. The next section delves into the relationship between learning outcomes and the emergence of achievers and underachievers, including factors contributing to students' under-and over-achievement. These factors include home conditions, peer relations, physical and mental well-being, psychological state, academic inclinations, and aspirations and prospects. Finally, the article discusses teachers' important role in improving student learning outcomes. In conclusion, teachers can provide targeted interventions and support to improve their learning outcomes by understanding the factors contributing to students' successes and failures. The paper has significant implications for educators, policymakers, and researchers and can contribute to developing effective educational interventions to improve student success.