Objectives <p>Lipoprotein(a) [Lp(a)] was related to increased risk of major adverse cardiovascular events. We aimed to explore the association between Lp(a) levels and intracranial plaque vulnerable features identified through high-resolution magnetic resonance imaging (HRMRI), along with their prognostic significance.</p> Materials and methods <p>A total of 210 consecutive patients with symptomatic intracranial atherosclerosis stenosis (sICAS) who underwent Lp(a) measurement and HRMRI were retrospectively collected. Plaque vulnerable features were defined as intraplaque hemorrhage (IPH), positive remodeling, plaque surface irregularity, and grade 2 plaque enhancement. Binary classification of Lp(a) levels was applied to assess its relationships with plaque features and long-term stroke recurrence using Cox proportional hazard models.</p> Results <p>Patients with a high Lp(a) level had a higher presence of IPH (30.59% versus 52.50%, <i>p</i> = 0.01), surface irregularity (26.47% versus 47.50%, <i>p</i> = 0.02), and positive remodeling (40.00% versus 62.50%, <i>p</i> = 0.02). Over a median follow-up period of 32.5 months (Q1–Q3: 14.0–56.3 months), higher Lp(a) levels were linked to stroke recurrence risk (HR = 2.65; 95% CI: 1.28–5.47; <i>p</i> = 0.009). In a 4-group classification according to Lp(a) and plaque vulnerable features, patients with high Lp(a) and ≥ 2 vulnerable plaque features had the highest risk of stroke recurrence (45.5%; <i>p</i> = 0.004). Causal mediation analysis indicated that approximately 27.0% of the prognostic impact of Lp(a) was mediated through vulnerable plaque features.</p> Conclusion <p>Elevated Lp(a) levels are linked to an increased stroke recurrence risk in sICAS patients, with part of this effect mediated by vulnerable plaque characteristics.</p> Key Points <p><Emphasis Type="BoldItalic">Question</Emphasis> <i>Lipoprotein(a) [Lp(a)] is a causal risk factor for atherosclerotic cardiovascular disease and plaque vulnerability, but the simultaneous evaluation of Lp(a) and vulnerable plaque features remains unknown.</i></p> <p><Emphasis Type="BoldItalic">Findings</Emphasis> <i>Elevated Lp(a) levels are independently associated with vulnerable plaque features, all of which are linked to clinical outcomes.</i></p> <p><Emphasis Type="BoldItalic">Clinical relevance</Emphasis> <i>This might offer novel targets to mitigate the atherogenic impact of Lp(a) and provide a clinically available, noninvasive tool for monitoring the clinical benefits of Lp(a)-lowering therapies in the future.</i></p> Graphical Abstract <p></p>