Do I need to learn music theory to become proficient with Guitar?

I do not think so. Being proficient at playing the guitar is different from being able to compose or improvise (ad hoc composition) new music.
And besides, music theory is just a theory lol.

No, but it will make any musical experience richer and more interesting and thus, more fun.

If you understand, for example, the scales, then the chord structure become clearer.

If you understand what a theme is, then the variations have more meaning.

If you understand the rhythm scheme, then the various beats make sense.

If you love music, why not learn something about theory, melody, harmony and rhythm? (You can always unlearn it.)

A ton of very successful musicians never learned to even read music..

However, if you plan on making very rich and interesting music, @gailcalled is correct. I’ve found though, that oftentimes the music that I enjoy is much more simple. It all depends on the style you intend to play and the target “audience”... even if that audience is only you.

Knowledge of musical theory can be a benefit but the lack of it would not prevent someone from becoming a great guitarist. They would be somewhat handicapped working with better educated musicians who understand key signature and timing notation.

Nope. You don’t need theory to play. For many people, it’s far easier to play without theory. They play by ear and it works.

Theory helps you figure stuff out if you can’t hear it, or if it takes too long to get it by ear.

Theory will help you play better, but it is not the only way to become proficient.

Theory will help you improvise, sorta. That is, you can figure out what notes will fit. But generally, that takes too long. By the time you figure out what note to play, you are way past the time to play it. On the other hand, it is likely that it will come around again.

I think that the thing that will help you most with improvisation is knowing your scales. Know what key you are in, and know how to play the notes in that key, and you’ll be able to fit right in.

It also helps to know where you are in the tune. Theory can help, but usually it’s something you just need to feel.

But the biggest tip I can give you on improvisation is to listen. Listen to what everyone else is doing instead of hogging all the space for yourself. By listening and giving to your fellow musicians, you open things up, and that makes the music a lot better. People who hog all the space are not liked.

Disagree with the above. I’ve found music theory quite valuable in helping me learn to play the guitar.

Absolutely! If you are going to play music that you did not write and want to do it justice, learn to read it. Without theory, you don’t read music. You might read notes, but you guess at the rest!

Theory will help you, although it may not be necessary. You will understand what you are doing better. Ear training is also great, because with it you can better hear what you are playing, and be better connected to the music you play.

I think in the case of most guitar playing a little theory goes a long way in the hands of someone who really enjoys or wants to enjoy playing guitar. Knowing and/or understanding scales, keys and a few other structural elements will help make playing songs an “inside out” process rather than “outside in” and will probably save some time and effort with learning and internalizing songs.

There’s some good information here.

Music, above all, is about feeling. It was developed long before anyone had a theory to explain it. If you can’t feel it, the theory is worthless. If you can feel it, theory is unnecessary.

Theory does help, but it helps you intellectually. It helps you work things out. But it does not help you while you are playing, unless you are super super intelligent, and even then, I’m not convinced. You have to have memorized things in order to draw on them during play. You can’t figure it out in real time. It happens too fast for that.

I improvise all the time. It takes me a little while to figure out what scale I’m in. Once I do, I’m fine. I can listen to what my fellow musicians are doing and I can play notes that fit in. If I do play a “wrong” note, I know how to turn it into a right note, by playing it again. And again, until it sounds like I meant it that way. That’s what most good improvisers do. Make mistakes and turn them into intentions.

Classical music is different, of course, since you have to play as written without mistakes. If you make mistakes, everyone knows. It’s embarrassing. Classical music is for high stakes gamblers, it seems to me. Improvisation is for those who can’t handle that kind of pressure, like me.