Introduction: The present study examined the between- and within-person associations among negative weight-related experiences, weight bias internalization, and body shame, embarrassment, and pride in adolescents. Methods: Participants were 93 Canadian students (M[subscript age] = 15.54, 59.10% girls, 40.86% white) who completed a 5-day daily diary study in 2021. Multilevel models were estimated to examine the between- and within-person associations, as well as the cross-level interactions. Results: Fifty-nine negative weight-related experiences were reported from 22 participants (23.66%) over the 5-day study period. Adolescents with higher average negative weight-related experiences (OR = 19.60, 95% CI = 1.90-202.67) and weight bias internalization (OR = 3.66, CI = 2.07-6.46) had greater odds of reporting shame. Similarly, higher average negative weight-related experiences (OR = 16.29, CI = 3.65-72.75) and weight bias internalization (OR = 2.08, CI = 1.53-2.82) was associated with greater odds of embarrassment. No within-person effects were noted, such that reporting more negative weight-related experiences or weight bias internalization than one's own average was not related to body emotions. Conclusions: This distinction underscores that the persistent, rather than episodic, aspects of negative weight-related experiences and weight bias internalization are most impactful on adolescents' body image. These findings have implications for recruitment and screening for individual-level interventions for internalized weight bias and body image, and highlight the need for system-level policies and changes that prohibit negative weight-related experiences and messages to reduce likelihood of internalizing weight bias among adolescents.