Ludwig Iselin (2 July 1559 – 20 December 1612) was a Basel scholar. He was the son of Johann Ulrich Iselin and Faustina Amerbach. His father died during the plague in 1564 so young Ludwig grew up with his uncle, Basilius Amerbach (the younger).
He studied in Geneva with the famous Calvinist theologian Theodore Beza (1581), then in Bourges with Jacobus Cujacius (1582) and in Padua (1586). During his studies in Padua, he visited Italy – Florence, Rome and Venice.
After studying in Italy, he returned to Basel, where in 1589 he obtained the title of doctor of both laws and became a city syndicate (Stadtsyndikus). In 1610 he obtained the title of professor of Roman law.
In the years 1597-1598 and 1607-1608 he was rector of the University of Basel. He married Anna Ryhiner, daughter of Emanuel Ryhiner. He had seven children, six of whom died during the plague of 1610-1611. He himself died at a young age shortly afterwards, on 2 December 1612.
Ludwig Iselin is the author of many works, including memoirs. Most of them, however, have not been published.