<p>Nitrous oxide (N<sub>2</sub>O) is an important greenhouse gas and it can also generate nitric oxide, which depletes ozone in the stratosphere. It is a common target species of ground-based FTIR near-infrared (TCCON) and mid-infrared (NDACC) measurements. Both TCCON and NDACC networks provide a long-term global distribution of atmospheric N<sub>2</sub>O mole fraction. In this study, the dry-air column averaged mole fraction of N<sub>2</sub>O (X<sub>N<sub>2</sub>O</sub>) from the TCCON and NDACC measurements are compared against each other at seven sites around the world (Ny-Ålesund, Sodankylä, Bremen, Izaña, Reunion Island, Wollongong, Lauder) in the time period of 2007–2017. The mean differences in X<sub>N<sub>2</sub>O</sub> between the TCCON and NDACC (NDACC-TCCON) at these sites are between −3.32 and 1.37 ppb (−1.1–0.5 %) with the standard deviations between 1.69 and 5.01 ppb (0.5–1.6 %), which are within the uncertainties of the two datasets. The NDACC N<sub>2</sub>O retrieval has good sensitivity throughout the troposphere and stratosphere, while the TCCON retrieval underestimates a deviation from the a priori in the troposphere and overestimates it in the stratosphere. As a result, the TCCON X<sub>N<sub>2</sub>O</sub> measurement is strongly affected by its a priori profile. </p> <p> Trends and seasonal cycles of X<sub>N<sub>2</sub>O</sub> are derived from the TCCON and NDACC measurements and the nearby surface flask sample measurements, and compared with the results from GEOS-Chem model a priori and a posteriori simulations. The a posteriori N<sub>2</sub>O fluxes in the model are optimized based on surface N<sub>2</sub>O measurements with a 4D-Var inversion method. The X<sub>N<sub>2</sub>O</sub> trends from the GEOS-Chem a posteriori simulation are very close to those from the NDACC and the surface flask sample measurements (0.9–1.0 ppb/year). The X<sub>N<sub>2</sub>O</sub> trends from the TCCON measurements are slightly lower (0.8–0.9 ppb/year) due to the underestimation of the trend in TCCON a priori. The X<sub>N<sub>2</sub>O</sub> trends from the GEOS-Chem a priori simulation are about 1.25 ppb/year, and our study confirms that the N<sub>2</sub>O fluxes from the a priori inventories are overestimated. The seasonal cycles of X<sub>N<sub>2</sub>O</sub> from the FTIR measurements and the model simulations are close to each other in the Northern Hemisphere with a maximum in August–October and a minimum in February–April. However, in the Southern Hemisphere, the modeled X<sub>N<sub>2</sub>O</sub> shows a minimum in February–April while the FTIR X<sub>N<sub>2</sub>O</sub> retrievals shows a minimum in August–October. By comparing the partial column averaged N<sub>2</sub>O from the model and NDACC for three vertical ranges (surface–8, 8–17, 17–50 km), we find that the discrepancy in the X<sub>N<sub>2</sub>O</sub> seasonal cycle between the model simulations and the FTIR measurements in the Southern Hemisphere is mainly due to their stratospheric differences.</p>