Groothusen is an old Langwurtendorf – a village on an artificially-built ridge – in the municipality of Krummhörn in western East Frisia on Germany's North Sea coast.

Frisian merchants stacked their goods here and were accommodated in the village if they needed to stay for any length of time.

Other Langwurtendorf villages in East Frisia are found near Groothusen including Grimersum (Krummhörn), Jemgum and Hatzum (Rheiderland), and in the centres of Oldersum (Moormerland) and in Nesse (Norder Marsch).

The gravestone of Adda von Meckenaborg, lady of Groothusen, from 1590, carved in blue stone is particularly fine.

As well as other impressive graves, the church has a splendid 1454 cast bronze baptismal font by Ghert Klinghe and a valuable organ by Johann Friedrich Wenthin (1798–1801) with unique flute tones.