Oak (/oʊk/) is a village in Nuckolls County, Nebraska, United States.

Oak was platted on its current site in 1888 when the Fremont, Elkhorn & Missouri Valley Railroad was extended to that point.

[4] According to the United States Census Bureau, the village has a total area of 0.15 square miles (0.39 km2), all land.

40.0% of all households were made up of individuals, and 3.3% had someone living alone who was 65 years of age or older.

41.9% of all households were made up of individuals, and 25.8% had someone living alone who was 65 years of age or older.

There were 5.0% of families and 17.5% of the population living below the poverty line, including 46.2% of under eighteens and 19.0% of those over 64.