Using data from the 1999 Trends in International Mathematics and Science Study (TIMSS), this study reveals that the Chilean students like and value mathematics, but have an inflated self-perception of their mathematic competence. Hierarchical linear models were used to predict mathematic achievement both at the student-within-class and class levels. At both levels, students' perceived difficulty of doing mathematics, expectations for further education, and beliefs regarding the causes of their mathematics outcomes were significant predictors of achievement. However, classes having more students liking mathematics had significantly lower mean scores. This later result is interpreted as the consequence of the more demanding curriculum and tougher grading standards used in higher performing classes