The 12th grade students are a group in constant exposure to stressful situations. Besides the physical and psychological changes that they experience during adolescence, they usually face the imminent completion of a series of decisions with important impact on their current and future lives. Seeking a better understanding of the most common and intense stress factors experienced by the Portuguese students, the authors built up the questionnaire and also the validation of the Inventory of 12th graders' Stress Factors (ISF - 12th). The study involved a total of 341students, all of them 12th graders from three schools from Northern Portugal. A Principal Component Analyses highlights a four dimension instrument with Cronbach's alphas varying between .72 and .93, and explaining 52% of variance. The results suggest the ISF as a valid instrument in the identification of the prevalence and intensity of stress factors among Portuguese 12th graders.
