guitar music theory
Guitar, Music Theory

Guitar Music Theory and Why You Should Learn

If you are learning the cello or the clarinet is might seem obvious that learning music theory will just go along with that as part of the deal. But what about the guitar? Most guitarists who play folk, rock, pop or even jazz guitar usually start off playing by ear. Many guitarists also start out by teaching themselves by copying what they hear and see on YouTube. But even those who take lessons will probably not cover a lot of theory, even with a teacher. Many guitarists think that learning theory is a waste of time for them, or, worse, that it might actually be bad for their playing. So I‘d like to take this chance to explode a few of these myths and show how a good grounding in guitar music theory can make any guitarist a better, more versatile and accomplished musician.

The Big Myth: Learning about theory makes you less “musical”

Although I have heard this argument so many times I never hear it from by someone who really understands music theory or is even a fluent sight reader. If you are passionate about your music and what you do, then learning music theory isn’t going to change that. Think about when you shift from a major to a minor chord. That feeling you get from the music isn’t going change just because you know which is which. In fact that knowledge can enhance your awareness of the mood you are creating because your brain starts telling you “ah here’s that lovely minor chord coming up”

So how can theory help you as a guitarist?

Assuming that you are playing folk or rock or a similar style, as opposed to classical, there are many ways that understanding the underlying rules and structure of music can help you even if you play mostly by ear.

Keep in mind that when we talk about the rules in music this doesn’t mean a set of rules which you must follow. It means the set of conventions that have evolved over time and which most musicians follow intuitively without thinking about it. For example, unless you were trying to do something strange and experimental, if a song starts on the note D, you won’t want to play an E flat chord along with it. That is not because it’s against the rules. It would just sound weird. Over time, through listening, we internalize these rules. But the more you understand about them, the more you can use them consciously to enhance your playing.

Chords and voicings

For guitarists, perhaps the most important aspect of music theory is the chance to learn about harmony and chord progressions. If you are accompanying a simple folk song and know what the key signature is, you can quickly work out what chords you should play. A basic song in G major will be based around the chords G, C, D and maybe E minor. With that knowledge, it is easy to play along even on first hearing as you won’t need to be scrambling around trying to pluck possible chords out of thin air.

Understanding chord structure and knowing how chords relate to each other also allows you to substitute different chords to make you accompaniment more interesting.

The guitar has a wide range compared with many other instruments. This means the same chord can be played in different ways on different parts of the fretboard. This adds a bit of variety to the same basic chord sequence. Understanding the construction of the chords means that it is easy to work out the different versions – or voicing – for yourself instead of consulting a chord chart, which will probably only have a few of the many variations.


When you improvise, you want to play something free and interesting, But you can’t just play anything. So what makes all those apparently random notes still manage to sound just right? The key to good improvisation chord and scales. Many effective lead guitar improvisations are simply variations on the scale, in particular, the five-note pentatonic scale which crops up repeatedly in jazz and other styles. Understanding chords and chord progression is a big help. By understanding how different keys relate to each other you know how far you can travel musically without getting out of key or accidentally playing something that doesn’t quite fit.

Written music helps you communicate your ideas

Music theory often starts with learning how to read and write staff notation. Although this is often seen as mysterious and difficult it is actually nothing more than a logical system of symbols. If you can read and write the English language you should have no problem with staff notation which is much less complex and a lot more logical! Getting to grips with this language gives you a way of recording and sharing your musical ideas other than simply by playing them, which isn’t always practical.

Of course, you will always hear people say that there are many great guitarists out there who have never learned any theory. And while that is, of course, true, the reality is that these musicians are pretty exceptional individuals. They have musical skills and talents that the rest of us can only dream of. But who knows? Perhaps they would have been even better if they had!

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