The oral mucosa is a unique tissue microenvironment, constantly exposed to environmental stimuli, including a rich and diverse community of commensal microbiota, second only to the small intestine. Yet, while host-microbiome interactions have been much studied in other barrier sites, how the local epithelial barrier and immune cell network maintain the balance between microbes and host is not well understood at this mucosal interface. Importantly, an imbalance between microbiota and host leads to a common oral inflammatory disease, periodontitis. A recent human single cell atlas of oral mucosal tissues has provided important insights into the cell populations and states within the oral mucosa in health and periodontitis but lacked spatial distribution of cell subsets. Nonetheless, we expect that location-specific functions of distinct cell subsets will be important both in tissue homeostasis and in the pathogenesis of periodontitis. Hence, our current project aimed to generate a spatial atlas of human oral mucosa in health and severe/untreated periodontitis, using single cell resolution 450-plex spatial transcriptomics (10x Genomics, Xenium), and 18-plex spatial proteomics (iterative bleaching extends multiplexity, IBEX) platforms, which we optimized for oral tissues. Our work provides spatial context for the diverse epithelial, vascular, stromal, and immune cell populations at this mucosa, and defines specialized niches within the oral tissue microenvironment. Within the epithelium, we focus on two distinct niches. The gingival (oral) epithelium displays marker expression consistent with structural integrity and innate defenses, as well as a myeloid-cell rich immune microenvironment. In contrast, the tooth-associated crevicular epithelium serves as a permeable barrier site with functionality indicative of antimicrobial defenses and active neutrophil recruitment. In the crevicular subepithelial space we document unique lymphoid structures which become expanded and obtain features consistent with tertiary lymphoid aggregates in the setting of periodontitis. Within these formations we find a zonation of T cells, APCs, B cells and immune-activated fibroblasts, with presence of plasma cells deeper in the tissue, in the setting of periodontal disease. Collectively, our work compiles a spatial atlas of gingival tissues, uncovering unique structural niches with inferred functionality linked to maintenance of tissue integrity, and to the onset of inflammatory pathology.