RATIONALE: Adjunct intra-arterial alteplase has been shown to potentially improve clinical outcomes in patients with large vessel occlusion (LVO) stroke who have undergone successful endovascular thrombectomy. Tenecteplase, known for its enhanced fibrin specificity and extended activity duration, could potentially enhance outcomes in stroke patients after successful reperfusion when used as an adjunct intra-arterial therapy. AIM: To explore the safety and efficacy of intra-arterial tenecteplase after successful endovascular thrombectomy in patients with LVO stroke. SAMPLE SIZE: To randomize 498 participants 1:1 to receive intra-arterial tenecteplase or no intra-arterial adjunctive thrombolysis therapy. METHODS AND DESIGN: An investigator-initiated, prospective, randomized, open-label, blind-endpoint multicenter clinical trial. Eligible patients with anterior circulation LVO stroke presenting within 24 h from symptom onset (time last known well) and excellent to complete reperfusion (expanded Thrombolysis In Cerebral Infarction (eTICI) scale 2c-3) at endovascular thrombectomy are planned to be randomized. OUTCOMES: The primary outcome is freedom from disability (modified Rankin Scale, mRS, of 0-1) at 90 days. The primary safety outcomes are mortality through 90 days and symptomatic intracranial hemorrhage within 48 h. DISCUSSION: The POST-TNK trial will evaluate the efficacy and safety of intra-arterial tenecteplase in patients with LVO stroke and excellent to complete reperfusion.