Pieter Cornelis (Piet) Emmer (born October 17 1944) is a Dutch Emeritus Professor of Colonial History at Leiden University, specialising in the European Expansion, and related themes of slavery and immigration.

He worked at the University of Amsterdam[2] (Faculty of Economic Sciences) where he obtained his PhD in 1974 with the thesis 'England, the Netherlands, Africa and the slave trade in the nineteenth century'.

[2] He then worked at Leiden University until 2009, as full professor of the history of European expansion and related migration and slavery.

As Visiting Professor, he was associated and taught at the University of Texas in Austin, the Universität Hamburg and the Université de Bretagne-Sud.

For years, Emmer was considered the slavery expert in the Netherlands, but his perspective has been criticized in the public debate.