Republican Democratic

The 2021 Nassau County Legislature Election was held on November 2, 2021, to elect the 19 legislators in Nassau County, New York, one from each of the county's legislative districts.

The elections coincided with the county executive and district attorney elections well as other elections to various cities, towns, and villages.

The Republican Party gained one seat, increasing their majority from 11–8 to 12–7.

Results of the 2021 Nassau County Legislature election by district: