Late adolescents differ in the degree to which they are thoroughly engaged in the study choice process and in the degree to which their choices are autonomous in nature. This study examined the unique and interactive roles of (a) parental involvement in the study choice process and (b) late adolescents' sense of having an authentic inner compass (AIC) in predicting their study choice decision-making. A cross-sectional questionnaire study was conducted among 331 12th-grade adolescents from the Flemish part of Belgium (68.3% female; Mage = 18.04, SD = 0.48) in the spring of 2017 and 2018. Results of the latent sum and difference models revealed that late adolescents experiencing a stronger AIC and more need-supportive parental involvement showed more engagement in and autonomous regulation of the study choice process. In contrast, when experiencing more controlling parental involvement or uninvolvement, late adolescents showed more controlled regulation, with parental control also being linked to less commitment. Although mothers were perceived to be more involved than fathers, maternal and paternal involvement were equally strongly related to the study choice tasks. Overall, late adolescents' sense of having an AIC and parental involvement were related independently to the outcomes, with sense of having an AIC yielding the strongest associations.