Schlatt-Haslen District is a district of the canton of Appenzell Innerrhoden in Switzerland . It was formally established in 1872 from the rhode Schlatt and the village Haslen.

Slatte either refers to hollow or slope, to the local dialect word schlatt which means hitting. The name of the village Haslen goes back to Haslowe which means a pasture with hazelnut trees.

Schlatt is first mentioned in 1200 as Slatte. In the 13th century, Haslen was mentioned as Haslowe.