The canton of Saint-Omer-Sud is a former canton situated in the department of the Pas-de-Calais and in the Nord-Pas-de-Calais region of northern France.

It was disbanded following the French canton reorganisation which came into effect in March 2015.

The altitude varies from 0m (Saint-Omer) to 119m (Wizernes) for an average altitude of 38m.

The canton comprised 4 communes:[1]

This Pas-de-Calais geographical article is a stub.