This study investigates the relationship between high school students’ subjective wellbeing, English learning motivation, and English proficiency. Three sub-components of subjective well-being were included in this study: positive efficacy well-being, positive emotional well-being, and positive relationship well-being. In all subcomponents of subjective well-being, the mean value of female students was higher than that of male students. In addition, the students with upper and middle levels of English proficiency showed higher subjective well-being than those with a lower level. Among the subcomponents of subjective well-being, positive relationship well-being was found to have the most significant effect on both the ideal L2 self and the ought-to L2 self. Among English learning motivations, the higher the ideal L2 self, the higher the English proficiency. The subjective well-being and the ideal L2 self positively affected English proficiency. This study suggests that appropriate educational activities are needed to enhance students’ subjective well-being and form a concrete ideal L2 self.