Blue on blue may refer to:

• "Blue on Blue" (song), a 1963 hit song recorded by Bobby Vinton
  • Blue on Blue (Bobby Vinton album), 1963
• Blue on Blue (Leigh Nash album), 2006
• "Blue on Blue" (James Blunt song), a 2013 song by James Blunt
• "Blue on Blue" (Pet Shop Boys song), a c. 2006 song by the Pet Shop Boys

• "Blue on Blue" (Ugly Betty), an episode of Ugly Betty
• "Blue on Blue" (Under the Dome), an episode of Under the Dome

• Blue on Blue (book), a 2017 book about police misconduct by Charles Campisi and Gordon Dillow
• Blue on blue (military), inadvertent firing towards an allied NATO military force