Did you actually search the wiki at all before asking that question? A simple search of this wiki will tell you that there has been four wars in the series.

The global conflicts in the Naruto world, akin to our real World Wars, there were four of them in total. You can read the articles about each of them for better understanding:

• First Shinobi World War

• Second Shinobi World War

• Third Shinobi World War

• Fourth Shinobi World War