Patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) who no longer respond to platinum-based chemotherapy have few effective treatment options, and outcomes with current therapies are modest. This phase II, single-arm, multicenter study evaluated the combination of the PD-1 inhibitor penpulimab (200 mg) with the anti-angiogenic agent anlotinib (12 mg) in R/M HNSCC patients who progressed following at least one platinum-based chemotherapy regimen.Out of 38 enrolled participants, 13 (34.2%) achieved partial tumor shrinkage, while 16 (42.1%) maintained disease stability. Over a median follow-up of 7.06 months (range: 4.14–15.70), the objective response rate determined by independent review was 34.2%, and the overall disease control rate reached 76.3%. Median progression-free survival was 8.35 months (95% CI: 5.95–13.11). Twelve deaths occurred during follow-up, and median overall survival was not yet reached; the 12-month overall survival rate was 59.8%. Grade 3 or 4 treatment-related adverse events were observed in 47.4% of patients. Combining penpulimab with anlotinib demonstrated encouraging anti-tumor activity and an acceptable safety profile in R/M HNSCC patients after platinum therapy failure.