Stress has a negative impact on academic achievement, but it is unclear whether achievement impacts stress. Most stress research utilizes a unidirectional design (e.g., stress affects achievement). Recent research has begun to examine cross-lagged models in which social-emotional variables and achievement affect one another; however, associations have typically been found at the between-person level of analysis. In contrast, within-person effects may provide information about the state- or trait-like nature of an individual’s, versus a group’s (between-person effects), growth over time. This short-term longitudinal study examined the direction of relations between the social-emotional variable of perceived stress and literacy among diverse elementary students. In addition, this study was the first to examine stress-literacy achievement relations at both the between-person and within-person levels. Participants included upper elementary students (N = 397; Mage = 9.61; 56% female; 57% Dual Language Learners; 12% Black, 6% Asian, 30% Latinx, 7% Multiracial; 43% White) from three schools. Measures were collected at three timepoints over four months, including student-reported perceived stress (two factors: stress-coping and stress-distress) and a literacy achievement performance task (Test of Silent Reading Efficiency and Comprehension, TOSREC). Latent variable path analyses revealed that stress-coping was a significant predictor of later literacy achievement. Reverse relations also held true with literacy achievement as a negative predictor of later Time 2 stress-distress, and a positive predictor of later Time 2 coping, when previous stress was not a control. In contrast, no significant stress-literacy achievement relations (i.e., direct, reverse, or cross-lagged) were found when a latent curve model was used at the residual level, which suggests that the relations between stress and literacy achievement were more trait-based than state-based for students across a short period of time. Results are discussed in the context of reciprocal and between-person versus within-person mechanisms of change between stress and literacy achievement.