Rokytnice nad Jizerou (German: Rochlitz an der Iser) is a town in Semily District in the Liberec Region of the Czech Republic.

The name Rokytnice refers to the old Czech word rokyta (meaning 'willow', a common tree in the area).

The highest peak in the municipal territory is Sokolník at 1,384 m (4,541 ft), which is located on the border with Poland.

Rokytnice nad Jizerou is the starting point of the railway line to Martinice v Krkonoších.

[7] The main landmark of the town is the Church of Saint Michael the Archangel, located in Dolní Rokytnice.