Mitja Kolia Zastrow (born 7 March 1977) is a Dutch swimmer and an Olympic medalist.

He became a naturalized Dutch citizen in July 2003, after a conflict with the German Swimming Association.

In 2001, despite being the 100 meter freestyle champion in Germany, a hand injury kept him from attending the FINA World Championships in Fukuoka, Japan.

Zastrow qualified fifth out of one hundred Dutch swimmers to participate in the 2004 Summer Olympics in Athens, Greece.

Along with Pieter van den Hoogenband, Johan Kenkhuis, and Klaas-Erik Zwering, he was a member of the Dutch 4×100 meter freestyle relay team, which won silver by clocking in at 3:14.36.