This study is based on a sample of 332 Argentinean teenagers in their last year of secondary school. In the context of the relational theory of motivation, an attempt is made to determine the motivational categories best predicting Future Time Perspective (FTP) extension. The influence of the sex, locus of control, social class, and school ethos variables on FTP extension is also explored. A scale measuring locus of control and the Motivational Induction Method (MIM) have been employed to obtain the data. Through stepwise multiple regression, a predictive set is determined, made up of life-meaning values, self-fulfillment, academic achievement motivation, locus of control, sensual values, and social contact. Significant differences are found in FTP extension and locus of control in relation to school ethos. The Mann-Whitney and Kruskal-Wallis tests are used as statistical proof. A one-way ANOVA is run to examine the relationship between locus of control and school ethos levels. The possibility of a motivational profile common to Argentinean teenagers is considered and the pedagogical consequences of the findings are discussed. (Contains 5 tables.)