This study addresses a growing concern about the impacts of major selection dissatisfaction on psychological well-being among accounting students by using a Stimulus—Organism—Behavior—Consequence (SOBC) Framework. The findings revealed that students who are dissatisfied with their major selection when enrolling in university experience eroded psychological well-being because major selection dissatisfaction leads to low levels of academic motivation, resulting in poor academic engagement. Specifically, lack of academic motivation causes negative effects on all forms of academic engagement, including agentic engagement, behavioral engagement, emotional engagement, and cognitive engagement. Subsequently, a lower level of accounting students’ academic engagement in terms of behavioral and cognitive engagement worsens their psychological well-being. The findings highlight the importance of major selection when students consider accounting as a career, suggesting that students should explore and gather information related to the accounting major to ensure the accounting major fits their strengths, interests, and career objectives. Also, the findings provide insights for universities to realize students’ psychological needs when they experience major selection dissatisfaction. This understanding can inform the design of student support services and curriculum modifications to better students’ psychological well-being.