Neutrophils are increasingly recognized as functionally versatile immune cells, with tissue-specific phenotypes that extend beyond their classical role in acute inflammation. In osteoarthritis (OA), neutrophils are abundant in synovial fluid (SF) which has been linked to worse symptoms., yet their presence and function within the infrapatellar fat pad (IFP) remain poorly defined. Here, we characterized neutrophils in OA IFP using flow cytometry, immunofluorescence, proteomics, and functional assays. Weand identified a distinct population of HLA-DR⁺ neutrophils enriched in OA IFP. compared to matched SF. These cells co-expressed classical neutrophil markers and antigen presentation markers. Sorted IFP HLA-DR+ neutrophils induced proliferation of autologous CD3⁺ T cells, supporting a role in antigen presentation. Proteomic profiling of OA IFP revealed upregulation of metabolic and enzymatic activities as well as downregulation of apoptotic and enzyme inhibition pathways, consistent with the increased fibrosis and neovascularization observed histologically. Our findings suggest that IFP-resident neutrophils adopt a tissue adapted, antigen-presenting phenotype, with potential roles in T cell activation, fibrosis, and angiogenesis. Collectively, our findings expand the functional scope of neutrophils in arthritic diseases, further establishing their potential in antigen presentation, and positions the IFP as a previously underappreciated, immunologically active niche in OA pathogenesis.