AbstractThis research was conducted at an Indonesian university, explores the multifaceted impact of a mobile learning application (MLA) on cognitive learning outcomes (CLO), student engagement (SE), and mobile self-efficacy (MSE) within an introductory accounting course. Employing Richey and Klein's Design and Development Research (DDR) model, the study spans need analysis, design and development, and evaluation stages. Adopting a quasi-experimental approach integral to DDR methodology, the research employs t-tests and MANOVA to comprehensively assess MLA's effects on CLO, SE, and MSE. The study draws theoretical underpinnings from Bandura's socio-cognitive theory and Piaget and Vygotsky's constructivism theory, providing a robust framework for understanding the interplay of MLA within the educational context. Aligned with DDR principles, primary objectives encompass evaluating MLA's feasibility and gauging its impact on cognitive learning outcomes, student engagement, and mobile self-efficac.....