Federation-Klingon War
There have been several conflicts fought between the Klingon Empire and the United Federation of Planets.

 Federation-Klingon War (2256-57)
 Federation-Klingon War (2267)
 Federation-Klingon War (2372-73)
 Federation-Klingon War (alternate timeline) (after 2344)

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 Federation-Klingon Cold War