The Van Leer family, originally spelled Von Lohr, is an influential German–American family that emigrated to the Province of Pennsylvania in the 17th century from the Electorate of Hesse near Isenberg, Germany. The family made their fortune in the United States through the ironworks business. The family includes American business owners, academics, civil rights activists, women's rights activists, university founders, inventors, politicians, and military officers. Earlier spellings include Von Leer, Von Lohr, and the ancient surname Valär.

The family is first mentioned in 1396 and their coat of arms was registered at the Battle of Grandson in 1476. They later held prominent positions within the Saffran Guild in Zürich before moving to Hesse and Mainz. They maintained close relations with the House of Matsch during the end of the 15th century Johann Georg von Lohr sometimes as "von Leer" founded the America branch in 1682 as one of William Penn's first investors. He was the first to use the spelling Van Leer.