Recent research has shown that lower social class students are more likely to endorse performance-avoidance goals (i.e., the fear of performing poorly) than higher-class students, particularly in situations of success. The purpose of the present research is, first, to test the upward mobility process as a moderator of the link between social class and performance-avoidance goal endorsement. The second aim is to document the further impact of this process on academic performance. Two hundred and fifteen high school students (M age = 17.40, SD = 0.69) participated in the experiment. Half of them were randomly assigned to a “mobility salience” condition where they completed a mobility perception scale; while the other half completed a neutral scale. Then, they answered performance-avoidance goal items and solved mathematics, physics and life and earth sciences exercises. Results indicated that the salience of the mobility process increased the effect of social class on both performance-avoidance goal endorsement and mathematic performance. In addition, performance-avoidance goals appeared to be a mediator of the interaction effect between social class and the salience of the mobility process on mathematics performance. No such findings were obtained for physics and life and earth sciences. Taken together, these results support the idea that the prospect of experiencing mobility may be one of the mechanisms behind the difficulties encountered by lower-class students in an academic context.