The surface-atmospheric exchange of nitrous oxide (N₂O) was investigated in the vegetated littoral zone of a eutrophied midboreal lake (Lake Kevätön, Finland) with a static chamber technique. During a dry summer (three to six samplings per site), the meadow site and two marsh sites in the temporarily flooded eulittoral zone and the Phragmites australis-dominated site in the continuously flooded infralittoral zone had mean daytime N₂O-N emissions from 11 ± 7 to 22 ± 7 μg m⁻² h⁻¹, whereas the Nuphar lutea-dominated site in the infralittoral zone had a mean N₂O flux close to zero. During a wet summer (13–14 samplings per site), the mean daytime N₂O-N fluxes ranged from 4 ± 1 to 15 ± 5 μg m⁻² h⁻¹ at the three eulittoral sites and were negligible at the two infralittoral sites. The littoral zone occupied 26% of the lake area but was estimated to account for most of the N₂O emissions from the lake. The studied eulittoral zone, which did not have adjacent nitrogen fertilization, exhibited higher N₂O emissions during the summer than seen in northern natural ecosystems in general, including peatlands, forests, and the pelagic regions of lakes. Thus in lake-rich landscapes the littoral zone and other lake-associated wetlands must be considered as potential sources of atmospheric N₂O. An assessment of their atmospheric importance requires further data on the N₂O fluxes and their regulation in different littoral areas and on the total littoral coverage, neither of which is yet available.