In the present studies I investigated whether college students’ perceptions of effort source influenced their perceptions of the relation between levels of their own effort and ability in mathematics. In Study 1 (N = 210), I found using hypothetical vignettes that perceptions of task-elicited effort (i.e., effort that arises due to the subjective difficulty or ease of the task) led to perceptions of an inverse relation between one’s effort and ability, and perceptions of self-initiated effort (i.e., effort that arises due to one’s own motivation or lack of motivation) led to perceptions of a positive relation between one’s effort and ability, consistent with my hypotheses and prior research. In Study 2 (N = 160), participants completed an academic task and I used open-ended questions to manipulate their perceptions of effort source. I found that participants in the task-elicited condition endorsed no overall relation between effort and ability, and participants in the self-initiated condition endorsed an overall inverse relation, which is inconsistent with my hypotheses and prior research. Possible explanations for the findings, as well as broader theoretical and educational implications are discussed.