We develop an econometric model where the determinants of working while in school, academic performance, and the decision to drop out are set in the context of two types of high school students: those who prefer schooling and those who are more likely to join the labor market. The likelihood function of this model with heterogeneous preferences for schooling is composed of 48 individual contributions of a standard quadrivariate normal function. Exploiting a unique Canadian microdata set of high school students and school dropouts, we show that being a female student, attending a private school, and living with educated parents are linked to having a strong preference for schooling over the labor market. We also find that working fewer than fifteen hours per week while in school is not necessarily detrimental to success in school. Our results indicate that the decision to drop out is affected by the legal age to access the labor market, high minimum wages, and low unemployment rates. Several policies that aim at reducing the number of high school dropouts are identified.