Geertruy Haeck-van Slingelandt van der Tempel was a 15th-century Dutch patrician woman.

Geertruy was married to Adriaen Hermansz.

[2] After being widowed she entered the congregation of canonesses regular of St Agnes (Sint-Agnesklooster).

Around 1465 Haeck had her portrait painted kneeling in veneration of St Agnes.

This portrait was bought by the Rijksmuseum, Amsterdam, in 1957 for £4,300.