BACKGROUND: Tumor-infiltrating lymphocytes (TILs) are associated with decreased risk of recurrence in human papillomavirus-associated oropharyngeal squamous cell carcinoma (HPV(+)OPSCC). The composition and spatial distribution of TILs and tumor-infiltrating immune cells is not well characterized. METHODS: Formalin-fixed paraffin-embedded primary and lymph node (LN) tumor tissues from ten progressors (cases) and ten matched non-progressors (controls) were interrogated by imaging mass cytometry. Immune, stromal, and tumor cells were quantified from selected regions of interest (ROIs) using machine learning. Nearest neighbors, cell-cell interactions, and niche analyses were performed. RESULTS: In primary ROIs, immune cell, lymphocyte, T cell, CD8+ T cell, and innate cell prevalence was significantly greater in controls. High prevalence of immune cells, lymphocytes, innate cells, and CD4+ T cells in primary tissues was significantly associated with increased time to event (TTE). Although primary and LN prevalence of T cells, CD4+ T cells, CD8+ T cells, macrophages, and tumor cells were significantly correlated, differences in LNs were neither significant nor associated with TTE. Average distances between T cells and nearest B cells, and between lymphocytes and nearest tumor cells were decreased in control primary tissues. Interactions between B cells and T cells were less organized in primary tissues from cases. A niche predominantly comprising lymphocytes was associated with longer TTE. CONCLUSION: In HPV(+)OPSCC, immune cell subset prevalence in primary tumors differs with outcome and is associated with TTE. Interactions between B cells and both T cell subsets are associated with longer TTE, underscoring the importance of active intratumoral immune responses in outcomes.