Olędrzy

thumb|right|A historical Mennonite cemetery in Stogi, [[Poland]] thumb|right|An 18th-century Mennonite house in Żuławki, Poland Olenders ( or Olendrzy, singular form: Olęder, Olender; ) were people, often of Dutch or Frisian ancestry, who lived in settlements in Poland organized under a particular type of law.

The term Olender has been used to describe two related, but slightly different, groups of settlers. First, it describes settlers in Poland from Frisia and the rest of the Netherlands, most often of the Mennonite faith, who in the 16th and 17th centuries founded villages in Royal Prussia, along the Vistula River and its tributaries, in Kuyavia, Mazovia and Greater Poland. They settled in great numbers in Gdańsk. They possessed knowledge of flood control, and a well-developed agrarian culture. At that time, they were the wealthiest group of peasants. They maintained personal freedom, and their own religion and beliefs. After the First Partition of Poland, some of them emigrated to southern Ukraine.