Şimleu Silvaniei (Hungarian: Szilágysomlyó) is a town in Sălaj County, Transylvania, Romania with a population of 16,036 people (2002 census).
In 1919, the first Romanian-language high school in Sălaj county was founded here, and today the town is home to three high schools.
Romania's first Holocaust Memorial Museum was dedicated here in September 2005 by Dr. Alex Hecht and Adam Aaron Wapniak. The museum centerpiece is a synagogue originally built in 1876. The Museum is open daily, offering guided tours.
In antiquity, Şimleu Silvaniei was a Dacian fortress called Dakidava.