The musical score most commonly associated with the franchise was composed by father-and-son duo Keith and Matthew Strachan. The Strachans' score provides drama and tension, and unlike older game show musical scores, Millionaire's musical score was created to feature music playing almost throughout the entire show. The Strachans' main Millionaire theme song takes inspiration from the "Mars" movement of Gustav Holst's The Planets, and their question cues from the £2,000 to the £32,000/£50,000 level, and then from the £64,000/£75,000 level onwards, take the pitch up a semitone for each subsequent question, in order to increase tension as the contestant progressed through the game. On Game Show Network (GSN)'s Gameshow Hall of Fame special, the narrator described the Strachan tracks as "mimicking the sound of a beating heart", and stated that as the contestant works their way up the money ladder, the music is "perfectly in tune with their ever-increasing pulse".

The Strachans' Millionaire soundtrack was honoured by the American Society of Composers, Authors and Publishers with numerous awards, the earliest of them awarded in 2000. The original music cues were given minor rearrangements for the U.S. version's clock format in 2008; for example, the question cues were synced to the "ticking" sounds of the game clock. Even later, the Strachan score was removed from the U.S. version altogether for the introduction of the shuffle format in 2010, in favour of a new musical score with cues written by Jeff Lippencott and Mark T. Williams, co-founders of the Los Angeles-based company Ah2 Music.

List of soundtracks

Intro soundtracks
Since 2008
Preliminary rounds
Meet the Contestants
Fastest Finger First
4 Answers in Order
Results Revealed
Fastest Finger selected
In the Hot Seat
Explain the Rules
Questions 1-5: Let's Play
Questions 1-5
WWTBAM - £500 £1,000 Music question UK 2007

WWTBAM - £500 £1,000 Music question UK 2007

Questions 1-4 Correct
Questions 1-5 Wrong
Question 5 Correct
Question 6
Question 6: Final Answer
Question 6: Correct
Question 6: Wrong
Question 7
Question 7: Final Answer
Question 7: Correct
Question 7: Wrong
Question 8
Question 8: Final Answer
Question 8: Correct
Question 8: Wrong
Question 9
Question 9: Final Answer
Question 9: Correct
Question 9: Wrong
Question 10
Question 10: Final Answer
Question 10: Correct
Question 10: Wrong
Question 11
Question 11: Final Answer
Question 11: Correct
Question 11: Wrong
Question 12
Question 12: Final Answer
Question 12: Correct
Question 12: Wrong
Question 13
Question 13: Final Answer
Question 13: Correct
Question 13: Wrong
Question 14
Question 14: Final Answer
Question 14: Correct
Question 14: Wrong
Question 15
Question 15: Final Answer
Question 15: Correct
Question 15: Wrong
Say Goodbye to Contestants
4 Lifelines
Ask the Audience
Three Wise Men
Other soundtracks
Into the Commercial
Return from Commercial
Radio Edit
Out of Time Klaxon
Closing Theme
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