Dorothea von Velen (17 April, 1670 - 21 August, 1732) was the mistress of Johann Wilhelm, Elector Palatine. Born into an impoverished family of Berg nobility, she came to Johann Wilhelm's attention as a lady-in-waiting to his second wife, Anna Maria Luisa de' Medici. She bore Johann Wilhelm two children to survive to infancy, Frederika and Melusine, and is accredited with being the foremost advocate of religious toleration at the contemporary Palatine court, compelling Johann Wilhelm to issue the Religionsdeklaration of 1705.
At the age of 41, she married Otto Alexander, Bailiff of Seltz. It was a happy marriage, even though Dorothea failed to give him any children. When Johann Wilhelm died, in 1716, the new Elector, Charles III Philip, expelled her from her apartment in the Electoral Palace, believing her a stain on his late brother the Elector’s honour. For the last ten years of her life, she lived in extreme poverty, being entitled only to the widow's allowance of the Bailiff of Seltz. She died of dysentery.