The Cochinchina Campaign (French: Campagne de Cochinchine; Spanish: Expedición franco-española a Cochinchina; Vietnamese: Chiến dịch Nam Kỳ) is the common designation for a series of military operations between 1858 and 1862, launched by a joint naval expedition force on behalf of the French Empire and the Kingdom of Spain against the Nguyễn period Vietnamese state. It was the opening conflict of the French conquest of Vietnam.

Initially a limited punitive expedition against the persecution and execution of French (and to a lesser extent Spanish) Catholic missionaries in Đại Nam, the ambitious French emperor Napoleon III however, authorized the deployment of increasingly larger contingents, that subdued Đại Nam territory and established French economic and military dominance. The war concluded with the founding of the French colony of Cochinchina and inaugurated nearly a century of French colonial rule in Vietnam in particular and Indochina in general.