What Is Theme In Music? (Length, Usage & Examples)

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  • What is theme in music? 
  • How is theme different from melody?
  • Learn how to identify a theme and how to apply it to your music
  • Also, check out our guide to what contemporary music is.

You may have heard musicians discussing theme in music, and you might be wondering how to know when something is a theme versus a melody.

As we’ll soon find out, they can at times be used interchangeably, but not always. Not all themes are melodies, and not all melodies are considered themes in classical music.

Don’t worry, this isn’t as confusing as it sounds.

What Is Theme In Music?

A theme is the glue that holds a piece together and relates different melodies to each other. In classical music and film scores, an entire work may be structured around a single theme or a set of themes.

In traditional western music, theme typically refers to a brief melody that is repeated, expanded upon, and altered throughout the course of a piece.

In modern music, a song’s main instrumental riff can be thought of as a theme.

As we’ll soon find out, there are endless ways for a composer to both create and develop a theme.

In this article, we’ll look at some famous examples of theme and learn how a theme differs from a melody.

Is Every Melody A Theme?

There is a difference between a melody and a theme, but themes are almost always a melody.

The reason that not every melody is considered a theme is because a theme lays the foundation for other melodies to follow. Professional composers know how to expand and develop a theme to make it go farther, musically speaking.

Although there are pieces where every melody is a different theme, these are the exception rather than the rule.

For example, in a film score, it would be exhausting to listen to two hours of different themes! Instead, film composers have themes preceded by introductory music or followed by melodies that help develop the original theme.

Interested in more theory and songwriting? Make sure to check out What Is ‘Accent’ In Music?

How Long is A Theme According To Music Theory?

A theme is usually a short melody of about four measures or less. However, this is not a hard and fast rule, so themes can be longer or shorter.

The term ‘theme’ can have a number of meanings in music. In theory terms, theme may refer to the main melody of the piece from which the rest of the piece derives. In this context, a theme tends to be a single phrase that is several measures long.

A phrase is a part of a melody that feels complete by itself. Phrases are usually four or eight measures in length.

Themes Throughout History

Over the decades, the concept of theme has changed and evolved over time.

An understanding of where theme came from and where it is now can inform your perspective on themes in today’s songs.

Theme in Baroque Music

In Baroque music (the European style that came before classical music), a fugue’s subject may be thought of as a theme.

It is the main melody of the piece which is repeated and developed in other voices. A subject is often just a couple of measures long.

A famous example of theme in a Baroque fugue is Bach’s Fugue in C Minor. Pay attention to how the piece starts with just the theme (subject), followed by another melody.

This second melody is called the answer. The subject and answer are the foundations of everything else that happens in the piece.

Theme In Classical Music

In classical music, theme began to refer to distinctive melodies that were four to eight measures long. This is more similar to what musicians consider to be a theme today.

One of the most iconic themes ever written was the theme of the first movement of Beethoven’s 5th Symphony, occurring in the first four measures.

If you listen to the whole movement, you can hear references to and repetitions of that theme throughout.

Theme In Romantic Era Music

Another meaning of theme in music is its use as a leitmotif or idée fixe.

This is a very short melody that is associated with a particular character that recurs throughout an opera, musical, or programmatic symphony. It’s very similar to our modern concept of theme in film scores.

French composer Hector Berliosz had a theme (idée fixe) to represent his love, Harriet. This theme is woven throughout all five movements of the symphony.

How is Theme Used In Film Scores?

Today, many people use the term theme to refer to a melody in a film score that is associated with a particular character.

John Williams’s scores to the Star Wars movies have some of the most instantly recognizable themes, such as the Darth Vader theme and the Jedi theme.

If you pay attention to film scores while watching movies, the themes don’t just play when you see the characters on screen.

Sometimes the themes play in moments that reveal details that the words and action don’t. Themes may be used to foreshadow things to come or tell of events that took place in the past.

Themes can also help the audience understand what kind of person a character is, as the Darth Vader theme does in Star Wars.

How Can A Theme Be Developed In a Song?

A theme can be developed in a song by altering the rhythm, harmony, instrumentation, and background accompaniment.

Rhythmic changes can include playing the theme faster or slower or changing the length of certain notes in a theme for emphasis. You may also hear a theme played in different time signatures throughout a song or film score.

A song’s theme can be changed harmonically by transposing it to a new key.  Harmony changes can also include playing different chords in the accompaniment while the melody stays the same.

You may even hear a theme switched from major to minor or vice versa to indicate a change in the emotions of a character, or a victory or setback in a movie’s plot.

A theme can develop and take on new meaning through changes in the orchestration. You may hear a theme played in a high flute to sound playful and light-hearted and then hear the same theme later in the low part of a trombone’s range to sound menacing.

Themes also take on a different meaning depending on what the other instruments are doing.

A theme played by a single violin will mean something different than the same theme played with a driving drumbeat and busy synth patterns in the background.

Composers may change the accompaniment throughout a song or film to bring variety to the theme.

How Can Theme Be Used in Modern Music Production?

Today, a song’s main riff has a similar function to a theme in classical music. A strong riff is recognizable in just a couple of seconds. It will appear repeatedly throughout a song as a sort of reprieve from the vocal melodies.

For example, Yeah! by Usher has a synth riff that immediately tells listeners what song it is.

Sometimes, a song has a theme that isn’t a melody, but a drum rhythm. One of the most famous examples is We Will Rock You by Queen, with the stomps and claps that play throughout the whole song.


A theme is a recognizable element of a song that is repeated and developed over time.

A theme helps hold together a piece or helps identify characters in a movie. A theme can be a melody in a classical piece, film score, or a riff in modern rock and pop music.

As we’ve shown you today, there are endless ways to create and develop a theme on your own. Once you’ve got the core of your theme established, you are free to tweak the scale, tempo, rhythm, and timbre in order to tell a story with it.

If you want to learn more about music theory, you can check out these articles: