The recent, sudden growth of short-form video platforms, such as TikTok, has prompted public concern regarding short-form video addiction (SVA), a potential behavioral addiction with adverse health and social consequences. Whereas stress is positively related to SVA, research investigating its underlying psychological mechanism is warranted. Based on the self-regulatory executive function model, this study examined the potential mediating roles of metacognition and motives for short-form video use in a snowball sample of 422 participants, aged 15–66 years (36.3% male; M = 26.55, SD = 11.38), via an anonymous online survey. Consistent with the results of structural equation modeling, those of path analysis supported the mediating roles of metacognition (i.e., positive beliefs about worry [POS] and negative beliefs about worry [NEG]) and motives (for escape/coping). To be specific, the significant mediators of the stress-SVA link were POS (β = 0.041, 95% CI [0.006, 0.081]), NEG (β = 0.102, 95% CI [0.026, 0.180]), escape motive (β = 0.052, 95% CI [0.010, 0.103]), as well as NEG and escape motive serially (β = 0.039, 95% CI [0.008, 0.079]). Our findings suggest not only the central role of metacognition, through which stress activates one's motives to use short-form video to escape/cope, contributing to SVA, but also the risk-enhancing roles of NEG and escape motive in explaining the metacognitive-motivational mechanisms underlying the positive association between stress and SVA. Intervention programs for behavioral addictions, including SVA, may consider regulating metacognition of individuals, especially those under high levels of stress.