Abel Seyler (23 August 1730, Liestal – 25 April 1800, Rellingen) was a Swiss-born theatre director and former merchant banker, who was regarded as one of the great theatre principals of 18th century Europe. He was "the leading patron of German theatre" in his lifetime, and is credited with introducing Shakespeare to a German language audience, and with promoting the concept of a national theatre in the tradition of Ludvig Holberg, the Sturm und Drang playwrights, and German opera. Already in his lifetime, he was described as "one of German art's most meritorious men."