["Journal of Research on Adolescence, Volume 36, Issue 2, June 2026. ", "\nAbstract\nThe increasing prevalence of problematic short‐form video use among adolescents has raised concerns regarding its potential impact on academic engagement. This study aimed to investigate the bidirectional relations between them over time. Study 1 involved a three‐wave survey over three semesters, including 1227 Chinese adolescents at baseline (T1), with 1096 and 1077 retained at T2 and T3, respectively (Mage at baseline = 16.00, SD = 0.61, age range = 14–19; 56.6% girls). Two random intercept cross‐lagged panel models were estimated, showing that problematic short‐form video use and academic engagement negatively predicted each other over time, both in the behavioral and emotional engagement. Moreover, goal focus was found to mediate the effect of problematic short‐form video use on academic engagement. Study 2 involved a two‐wave survey of 898 Chinese adolescents at baseline (T1), with 507 retained at T2, over a 10‐month interval (Mage at baseline = 15.89, SD = 0.74, age range = 15–18; 50.9% girls). A cross‐lagged network analysis showed that within the academic engagement, “Participation” had the strongest impact on problematic short‐form video use, while “Curiosity” was the most affected by it. Conversely, within the problematic short‐form video use, “Loss of control” was the most affected by academic engagement, whereas “Behavioral salience” most strongly affected academic engagement. These findings elucidate the mechanisms linking problematic short‐form video use and academic engagement, and suggest that focusing interventions on key nodes, including academic participation and the behavioral salience of short‐form video use, may be especially effective in enhancing adolescents' academic engagement.\n"]