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The mammalian pineal gland maintains normal circadian rhythms and homeostasis by secreting melatonin. However, the lack of a single-cell-resolved regulatory map limits our understanding of how these neuroendocrine functions are orchestrated. Here, we constructed a multiomics atlas of the pineal gland from Macaca fascicularis by integrating snRNA-seq, snATAC-seq, and spatial transcriptomics. We identified pinealocytes as the predominant cell type, alongside six glial and vascular lineages. Chromatin accessibility analysis delineated cell-type-specific regions enriched for melatonin synthesis and phototransduction genes. Notably, we resolved a dual-layer regulatory architecture: While melatonin synthesis programs are robustly organized, circadian clock regulators exhibit a distinct, sparse spatial pattern. Coexpression networks further identified core modules and regulatory hubs-including CRX/OTX2, LHX4, and RORA-that integrate these circadian and light-responsive signals. Cell-cell communication analysis identified signaling axes, such as PTN-ALK/SDC2, RA-RORB, and NRG1-ERBB4, that potentially coordinate this spatial functional organization. Integrating genetic traits showed that sleep and neuropsychiatric risk variants preferentially map to these pineal regulatory modules. Specifically, sleep-associated loci converged on MEIS1-linked elements, while bipolar disorder-associated loci highlighted candidate genes of RDH12 and SDK2. Overall, this study reveals the cellular diversity and spatial regulatory logic of the primate pineal gland, providing a physiological foundation for investigating circadian and neuroendocrine regulation in healthy and disease models.