The main purpose of this paper is to study how the observed differences in educational achievement of whites and nonwhites teenagers in the US can be explained within a context of social interactions with differentiated agents, where individuals differ in how they value their interactions with individuals of their same type and individuals from the opposite type.  We write a model where teenagers are allowed to interact with other teenagers and their degree of social interaction is differentiated inasmuch as whether they interact with their own group or other groups. Following an approach of differences in conditional variances, the conditions for the identification of the coefficient of differences in social interactions are established. Our estimation using the US census data on teenagers sustains the conclusion that there exist differences in the interaction coefficient between individuals of different types.  Individuals will value more their interaction with individuals from their own types as opposed to individuals in the opposite type.