thumb|Pieter Post in 1651. Portrait by Pieter Nolpe, detail of a larger work
Pieter Jansz Post (1 May 1608 - buried 8 May 1669) was a Dutch Golden Age architect, painter and printmaker.
Post was baptised in Haarlem, the son of a stained-glass painter and the older brother of painter Frans Post.[1] He is credited with the creation of the Dutch baroque style of architecture, along with his longtime collaborator Jacob van Campen. Together they designed the Mauritshuis in the Hague.[2] According to Houbraken he was a famous architect who introduced his brother Frans to Maurice of Nassau, Prince of Orange, while he was working on plans for the Mauritshuis.[3]
According to the RKD he became a member of the Haarlem Guild of St. Luke in 1623, and became painter and architect for Stadhouder Frederik Hendrik.[4] He was the overseer from 1640 for the new additions to Paleis Noordeinde in The Hague.[4] From 1645 he was the architect for Frederik Hendrik for Huis ten Bosch, where he worked together with Jacob van Campen.[4] He died in The Hague, aged 61.His son Maurits became an architect, and his son Johan Post became a painter,[4] and his daughter married the anatomist and collector Frederik Ruysch. His granddaughter Rachel Ruysch became a famous flower painter.