How many songs did claude debussy compose?

In 1977 musicologist François Lesure catalogued 141 distinct compositions by Claude Debussy. Debussy didn't use opus numbers.
Many of the compositions have multiple movements or are collections of etudes, poèmes, chansons, nocturnes, ballades, etc.; it is standard practice not to consider each individual piece as a separate composition.
If you wish to count up all the individual movements of Debussy's works, you can do so using the link below.

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Depends on whether by "song" you mean an actual song with words that are sung, or a composition for instruments, which for some reason are often called songs despite the lack of any singing. About 88 for piano and voice, 11 for soloists and orchestra (and possibly choir).