Saint-Alexandre-de-Kamouraska () is a municipality in the Canadian province of Quebec, in the Kamouraska Regional County Municipality.
Before July 5, 1997, it was known simply as Saint-Alexandre.
The parish of Saint-Alexandre was founded in the first half of the 19th century. It was canonically erected in 1851. The post office was first opened in 1854 under the name "Saint-Alexandre-de-Kamouraska". The parish municipality of Saint-Alexandre was then created in 1855. In 1997, its status was changed to a municipality alongside its name, which became Saint-Alexandre-de-Kamouraska.
On January 27, 1968, the westbound Scotian passenger train operated by Canadian National Railway derailed near the Saint-Alexandre-de-Kamouraska station. Two passengers were injured. The train was operating at about when an axle on the locomotive broke.
The following waterways pass through or are situated within the municipality's boundaries: