<p>Nitrous oxide (N₂O) is a potent greenhouse gas with radiative forcing 265&ndash;298 times stronger than that of carbon dioxide (CO₂). Increasing atmospheric N₂O burden also contributes to stratospheric ozone depletion. Recent field studies show N₂O emissions from the Arctic ecosystems have increased due to warming. To date, the emissions across space and time have not been adequately quantified. Here we revised an extant process-based biogeochemistry model, the Terrestrial Ecosystem Model (TEM) to incorporate more detailed processes of soil biogeochemical nitrogen (N) cycle, permafrost thawing effects, and atmospheric N₂O uptake in soils. The model is then used to analyze N₂O emissions from pan-Arctic terrestrial ecosystems. We find that both regional N₂O production and net emissions increased from 1969 to 2019, with production ranging from 1.2&ndash;1.3 Tg N yr^-1 and net emissions from 1.1&ndash;1.2 Tg N yr^-1 considering the permafrost thaw effects. Soil N₂O uptake from the atmosphere was 0.1 Tg N yr^-1 with a small interannual variability. Atmospheric N deposition significantly increased N₂O emission by 31.5 &plusmn; 3.1 %. Spatially, terrestrial ecosystems act as net sources or sinks ranging from -12 to 700 mg N m^-2 yr^-1 depending on temperature, precipitation, soil characteristics, and vegetation types in the region.</p>