The new δ¹⁵N record of sediment core SSD004_GC11 is combined with published regional datasets to produce a basin-wide Arabian Sea denitrification stack. Spectral and cross-wavelet analyses reveal dominant orbital-scale variability, with stronger obliquity influence in the southern basin and precession dominance in northern records. Coherent variability between δ¹⁵N records and atmospheric N₂O concentrations highlights orbital forcing as a key driver of long-term nitrogen cycling and greenhouse gas variability.