Kupfermühle (Danish: Kobbermølle, both names meaning "copper mill") is a village located north of Flensburg in Schleswig-Holstein, Germany. It is located near the Flensburg Fjord just south of the easternmost part of the Danish-German border.

Kupfermühle belonged to Bov Parish until the establishment of the present border in 1920 when the rest of the parish opted to become Danish. The village now belongs to the Gemeinde Harrislee.

Kupfermühle was the home of the first factory in Schleswig, which is the reason behind the settlement's name. The copper mill was founded by king Christian IV of Denmark in 1612 and produced finished copper products and later also products in brass. Among its products were pipes and sheet copper for copper roofs but also utensils such as buckets, pots, kettles and candlesticks. The copper production flourished in 1914 when the factory employed more than 200 workers. It went bankrupt in 1962.

Both the 17th century factory buildings and the workers' residences are preserved. The latter are known in Danish as nyboder and show great similarities with Christian's contemporary buildings in the Copenhagen district of Nyboder. The village is now home to a museum which displays a large number of copper and brass products produced by the mill.