Zollverein, a customs union of German states led by Prussia, 1819–71. (The word zoll means "duty," and verein, "union.") The union laid a foundation for establishing the German Empire in 1871.

The Zollverein was created to eliminate custom duties between several states in the German Confederation so that these states would have free trade among themselves. Another purpose was to establish a unified tariff on goods imported from the rest of the world. Revenue was divided among the members according to their populations and resources. The Zollverein was enlarged in 1834 and 1867 and in 1871 was merged into the new German Empire.