This Is War is the third studio album by the American rock band Thirty Seconds to Mars.

This Is War may also refer to:

• "This Is War" (song), a song by Thirty Seconds to Mars
• This Is War (Emily Kinney album), an album by Emily Kinney
• "This Is War", a song by Alter Bridge from the album Pawns & Kings
• "This Is War", a song by Bush from the deluxe edition of the album Black and White Rainbows
• "This Is War", a song by Five Finger Death Punch from the album F8 (album)