Sils or SILS may refer to: Places Sils, Girona, a municipality in the comarca of Selva in Catalonia, Spain Lake Sils (Catalonia), an ancient lake near Sils, Catalonia, Spain Lake Sils, a lake in the Upper Engadine in the Grisons, Switzerland Other Single Incision Laparoscopic Surgery UMass SILS, the Summer Institute in Leadership in Sustainability at the University of Massachusetts Amherst