Greetsiel Church, Gothic church building in Greetsiel, Germany

Greetsiel Church is a single-nave Gothic hall church built of brick between 1380 and 1410, dedicated to Saint Mary. Its walls lean visibly due to weak foundations, and the rectangular structure has partly walled-up, partly enlarged windows and entrances. A separate brick bell tower stands apart from the church, and a roof turret above the east gable carries a clock, a bell and a gilded copper weather vane shaped like a three-masted ship.

Greetsiel Church was built in two phases between 1380 and 1410 as the private church of the chieftain Haro Edzardsna, in Gothic style and of brick. Pope Boniface IX confirmed it in 1401, before completion, and it belonged to the Diocese of Münster until the Reformation. An extension was added under Count Edzard II.

The pulpit from 1669, carved with Baroque flower garlands, stands at the centre of the Reformed service, which has no altar or cross. Above the west entrance hang the coats of arms of the Cirksena family of Greetsiel and of the Swedish royal house of Vasa, linked to them by marriage. A blue-stone epitaph commemorates pastor Johann Michael Knottner, who fled the Palatinate, served six years in Pilsum and 39 years in Greetsiel, dying at 69 in 1684.

The brick bell tower stands apart from the church, as is common in East Frisia. The three bronze bells hang in a new wooden frame: the large one in the middle, the middle one above it, and the small one on the tower's ground floor, hidden behind a public bookshelf. The old cast-iron bells are set up in the churchyard.

The weather vane atop the roof turret is a gilded copper three-masted hulk with set square sails, made around 1730; the congregation calls it the oldest ship weather vane in Lower Saxony. The church tower also served as the zero point of the Emden district's coordinate system during East Frisian cadastral surveying around 1870.