5 Reasons Why Learning Music Theory Will Improve Your Guitar Playing

Man Playing Guitar

Learning to play guitar can feel like a complex and frustrating endeavor. If a player has zero understanding of Music Theory, they are missing out on a key piece of the “musical” puzzle.

Music Theory helps guitar players with:

  • Understanding why the composer chose specific chords for a song
  • Providing you with a map of the notes on your instrument
  • Improvisation, Knowing what notes to play over each chord
  • Ear Training
  • Transposing Keys

Here we will dive into five concepts of how a firm grip on Music Theory will drastically speed up your journey to mastering your instrument. No longer will the “pain” of taking on the new discipline outweigh the benefits of what learning it will provide for you. Honestly, it’s not that bad. Really, learning music theory is fun.

1. Understanding why the composer chose specific chords for a song

Before I ever had any idea about music theory, I was always baffled by how my favorite musicians could create such amazing-sounding songs. HOW DO THEY KNOW WHAT CHORDS SOUND RIGHT TOGETHER?

Well, it’s not by luck or magic. They understand the theory behind the groupings of notes being played.

It’s not a coincidence that if you’re learning a song that starts with a G Major chord (playing in the key of G), you’re bound to be playing a C Major and D Major chord at some point throughout that song. “C” and “D” are the respective 4th and 5th chords made out of the G major scale.

You see, every key/scale has a natural set of notes/chords that occur and always have the same relation to each other. For instance, (using G major as our example) if you play a G major in your progression and then move to a C major chord, you made a I-IV (1 to 4) transition. The “I” and “IV” chords of any scale always have the same sound/relation compared to each other when played in a sequence.

Now, if you’re thinking “Oh man, this is already sounding complicated”, don’t give up quite yet. It seems complicated at first, but if you stick with it, I promise your “Ah-Ha” moment will happen, and things will start to get a lot clearer.

Just know that if you understand the theory behind the chords of the key you are playing in, you will have a known, predictable set of chords/chord variations you can use to build out a piece of music.

2. Music Theory gives you a map of your instrument.

The first time you pick up a guitar, the fretboard looks DAUNTING. “There’s like a million different notes on this thing!!” Well, actually there are only 12 notes with multiple locations of each exact note/pitch along with higher and lower octaves of that note/pitch.

If you understand theory you can easily navigate across the fretboard because the notes are easier to find in relation to one another.

For instance, sticking with our “G to C” example from above. If you find any “G” note on the fretboard, staying in the same fret, if you move your finger to the adjacent higher/thinner string, you will be playing a “C” note. “C” is the 4th note of the G major scale and will always be in this location in reference to a “G” note.

Now, with that being said there is one exception to this rule (using the “G” string and “B” strings), and it is due to the way that the guitar is tuned. If you play any note on the “G” string of the guitar, the corresponding “4th or IV” note will be 1 fret higher on the “B” string.

A good example is just to play the open strings. If you play the open “G” string, the adjacent higher string is the “B” string and thus the “C or IV” note is found on the first fret of the “B” string. Confused? Read over it one more time and try it on the guitar.

Practicing the different Major Scales across the neck will GREATLY improve your understanding of the guitar fretboard and help to burn into memory the locations of each note.

3. Improvisation. Knowing what notes to play over each chord.

Theory knowledge gives you the ability to improvise over a given chord progression confidently. Strangely enough, you may even be able to create amazing-sounding improvisational melodies WITHOUT even knowing exactly what notes you are playing. Sounds weird, right?? Well, it’s true.

Imagine you are attempting to improvise over the chords in a song that is written in the Key of “G”. let us use a I-VI-IV-V progression. In “G” this progression would be “G major – E minor – C Major – D Major”.

Your knowledge of theory would let you know that this progression is straight out of the G Major scale. This means that you could use the G Major Pentatonic Scale over the entire progression and never hit a “bad” or “clashing note”.

You wouldn’t even necessarily have to know exactly which note you are playing as long you stick to only the notes found within the G major pentatonic scale.

Your Music Theory knowledge would also tell you that you could play each respective Pentatonic scale over a particular chord. When…

  • G major is being played, improvise using the G major Pentatonic
  • E minor is being played, improvise using the E minor Pentatonic
  • C major is being played, improvise using the C major Pentatonic
  • D major is being played, improvise using the D major Pentatonic

When it comes to improvisation, a foundation of theory lets you understand exactly which notes are appropriate over a given chord or chord progression.

4. Train your ears with music theory.

Using theory helps to train your ears to understand how the relationship between specific notes and intervals sound (an interval is simply the distance between two notes).

If your ear is trained to know how a certain interval sounds, you will quickly be able to know what change has occurred in a piece of music that you are listening to or trying to transcribe.

Your brain will start to memorize how those intervals sound. Let’s say you’re learning a piece of music by ear and find that the G major chord is being played in the song. Then the song transitions to playing an E minor chord. Your trained ear will instantly be able to recognize that this is a “I-VI” interval movement, and thus, an E minor chord is being played.

A great way to practice ear training is to play through a given scale numerous times so that the scale is internalized in your brain and ears.

Then have a friend play the root note of the scale (on piano, guitar, violin, or even voice) and let that note get established in your ear. Maybe even play it a few times but really internalize it. Then without looking, have that person play a different note out of the scale and try to guess what tone in the scale is being played.

Practice this for a while and soon enough, you’ll be able to CLEARLY hear the differences in the relationships of the notes. “Ah, that’s a fourth” or “That’s a minor second.” It works.

Note that the further distance away a note is, the harder it will be to recognize it. So in the beginning, keep the interval distance fairly short.

5. Transposing Keys.

Imagine this situation. You’re over at your bandmates house having a nice little Jam session with our “G” based “I-VI-IV-V” progression. Then of course, your prima donna singer feels like he’s putting a little too much work in on the song and says… “This is a little too high for me to sing over. Let’s try playing it in the key of “E” “.

Well, this is where your Music Theory superpowers kick right in, and you instantly respond with “No problem, I got this, easy.”

Because your theory knowledge lets you know that a “I-VI-IV-V” progression in the key of “E” is simply “E major, C# minor, A major, B major”. The work you put in understanding theory pays off.


Hopefully you found some insight and motivation within this article to commit to giving yourself the freedom of understanding your instrument. Learning theory really only seems difficult in the beginning and gets much easier as time goes on. Remember that your guitar playing journey is like sculpting a statue out of stone. Every little trick/concept/or skill that you can add to your arsenal is just one more chip off the block until finally, you’ve built your masterpiece.

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