Ter Aar (Dutch pronunciation: [tɛr ˈaːr] ⓘ) is a town and former municipality in the western Netherlands, in the province of South Holland.

It is located about 6 km northeast of Alphen aan den Rijn.

[1] At the former location of Langeraar, the new village of Aardam (52°9′57″N 4°42′40″E / 52.16583°N 4.71111°E / 52.16583; 4.71111) was built, near a bridge across the Aar.

North of Aardam, the hamlet Papenveer grew around a ferry across the Aar.

In 1817, the small municipality of Vrijhoeven was split off; it merged again with Ter Aar in 1841.