Background <p>Viscoelastic hemostatic assays provide rapid evaluation of clot initiation, propagation, and fibrinolysis and are increasingly used in neurocritical care. Their clinical value across traumatic brain injury, subarachnoid hemorrhage, and ischemic cerebrovascular disease remains uncertain.</p> Methods <p>We conducted an umbrella review of systematic reviews assessing thromboelastography, thromboelastography platelet mapping, or rotational thromboelastometry in neurocritical or neurovascular conditions. Eligible reviews included human participants and used reproducible search, selection, and appraisal methods. Two reviewers independently performed screening, data extraction, and methodological assessment. Overlap of primary studies was quantified using corrected covered area. Certainty of evidence was evaluated using GRADE. The primary outcomes were mortality, hemorrhage progression, delayed cerebral ischemia, and composite ischemic and bleeding events.</p> Findings <p>Four systematic reviews met eligibility criteria, comprising 73 study occurrences representing 63 unique primary studies. In traumatic brain injury and subarachnoid hemorrhage, viscoelastic assays consistently detected clinically relevant coagulation disturbances. Abnormal viscoelastic profiles were associated with increased mortality, radiographic hemorrhage progression, neurosurgical intervention, delayed cerebral ischemia, and early neurological injury severity; however, no review provided convincing evidence that VHA-guided interventions improved these outcomes. Evidence for thromboelastography-guided antiplatelet therapy in mixed ischemic stroke and coronary artery disease populations was associated with fewer composite ischemic and bleeding events, although mortality remained uncertain. Methodological quality across reviews varied, with only one review rated as moderate confidence.</p> Conclusion <p>Viscoelastic assays appear to have prognostic utility across neurocritical illness, but current evidence does not establish therapeutic benefit in traumatic brain injury or subarachnoid hemorrhage. The most favorable interventional evidence was identified for thromboelastography-guided antiplatelet therapy in mixed ischemic cerebrovascular and cardiac populations, although direct neuro-specific evidence remains limited. High-quality neuro-specific randomized trials and standardized assay thresholds are needed to clarify the clinical role of viscoelastic testing in neurocritical care.</p> Graphical Abstract <p></p>