The Prix de Seine-et-Oise is a Group 3 flat horse race in France open to thoroughbreds aged three years or older.
It is run at Maisons-Laffitte over a distance of 1,200 metres (about 6 furlongs), and it is scheduled to take place each year in late October or early November.
The event is named after Seine-et-Oise, a former department of France which encompassed parts of Paris.
The Prix de Seine-et-Oise was abandoned throughout World War I, with no running from 1914 to 1918.
The present system of race grading was introduced in 1971, and the Prix de Seine-et-Oise was classed at Group 3 level.