This study modeled the strain that academic demands (i.e., taking courses with demanding workloads) place on college students' academic performance by exploring how sources of student academic support and stress might explain this association. Student participants (N = 302) completed a survey about their most demanding class of the semester and reported on how demanding the class was, how much stress they experienced related to the class, and how often student peers communicated academic support in the class. A conditional process analysis revealed that (a) academic demands were positively associated with academic stress, (b) academic support from peers buffered the negative effect of stress on academic performance (moderation), and (c) academic demands produced a negative indirect effect on academic performance through stress, but this indirect effect was buffered by student academic support (moderated mediation). This study provides evidence that students earn lower grades when academic demands create stressors, but highlights the importance of peers communicating support in mitigating the effects of these stressors on grades.