High rates of failure in secondary level science classes are a problem worldwide. Effective teaching and efficient management of schools requires information as to the causes of failure. One approach to acquiring this information is to improve our understanding of what the students themselves perceive as the causes and antecedents of school failure. In this article, we analyze the perceptions of the factors of academic failure among grade-ten, science-tracked students. Students from eight schools in southern Portugal (N=346) participated in the study. The major factors of failure in 10th grade science courses, according to students, are quality of teaching and previous student preparation. One third of the students did not think that secondary science education prepared them for life in a scientific-technological society. A culture of high expectancy on the part of teachers, parents and administrators may be key to influencing rates of success.