Schlei

thumb|270px|Schlei in the village of Holm, Schleswig, Schleswig-Holstein|Schleswig thumb|Bilingual map of the Schlei (German and Danish placenames) thumb|Schlei nature park

The Schlei (; or ) is a narrow inlet of the Baltic Sea in Schleswig-Holstein in northern Germany. It stretches for approximately 20 miles (32 kilometers) from the Baltic near Kappeln and Arnis to the town of Schleswig. Along the Schlei are many small bays and swamps. It separates the Angeln peninsula to the north from the Schwansen peninsula to the south.