Bouches-de-l'Yssel (French: [buʃ.də.li.sɛl]; "Mouths of the IJssel"; Dutch: Monden van de IJssel) was a department of the First French Empire in the present-day Netherlands. It was formed in 1810, when the Kingdom of Holland was annexed by France. Its territory corresponded with the present-day Dutch province of Overijssel. Its capital was Zwolle.

The department was subdivided into the following arrondissements and cantons (situation in 1812):^[1]

• Zwolle, cantons: Hasselt, Kampen, Steenwijk, Vollenhove and Zwolle.
• Almelo, cantons: Almelo, Delden, Enschede, Goor, Oldenzaal and Ootmarsum.
• Deventer, cantons: Deventer, Hardenberg, Ommen and Raalte.

Its population in 1812 was 145,000, and its area was 340,000 hectares.^[1]

After Napoleon was defeated in 1814, the department became part of the United Kingdom of the Netherlands.