There's a great theory curriculum at Levine. DC has done three years and a year of sight singing. It's been a huge help in overall musicianship and deeper understanding. Seems important if your kid is a very serious musician, probably less so if not?

My child's piano teacher also formally teaches music theory.
His guitar teacher does not formally teach music theory, but does do things like refer to the pentatonic scale, chord families, and generally use music theory terms.
His music class in school also teaches some music theory, but is behind where he is from his piano teacher.

I think music theory is important and can lead to a deeper understanding of music. But it's also possible to become a casual musician and not really understand any theory.

I'm PP at 09:42.

As to your question of is it worth it, it depend entirely on you. Are you a musical family? Is it important that music be an integral part of your child's life?

It's only worth it if you value music in and of itself. There's no reason to pursue music theory for external benefits -- it doesn't make you smarter or a better person.

I'd say if you are a musical family and value music, then it's worth it. It's good foundation and make you a well-rounded musician.

I have my son in private piano lessons and I went through an extensive search to find the right piano teacher. So, he gets a good amount of theory infused into his lessons, but every teacher is different.

When I was growing up, I got minimal theory in my piano lessons. Basically, I learned how to read music, but that was all. In HS, I took the initiative to ask the band teacher for lessons in theory -- learning about major/minor scales, ear training, how to compose four part harmony. At that point in my life I was interesting in composing music.

You say that your child is learning one instrument at home, so I assume you are paying for private lessons. Talk to that teacher and mention to him or her what you think is missing and ask if that can be incorporated into the lessons. If the teacher is insufficiently knowledgeable about theory or if the teacher is unwilling, you might want to consider switching depending on how well everything else is going with him or her.

I think 5th grade is an ok time to start, earlier is definitely better. But if he can't actually play an instrument and read music yet, it's probably best to focus on that. You could definitely ask the teachers to include more, or do a workbook at home. I would only do formal theory when he can play all the notes on an instrument and read music easily.

Also, singing is a big part of ear training-- you might consider how that is developing.

If you have private lessons of any kind, I think theory should be included. With some teachers, you need to ask for it. If the teacher can't or won't incorporate it, I'd switch teachers. But that's just me. Also, our kids learned piano pretty easily and ate up the theory stuff. Different kid have different needs. But I do disagree with the pp who said 5th is too soon. I think it should be included from day 1, in an age-appropriate way. Ear training is also most valuable before age 10, according to something I recently read.

What are the instruments, and when did he start each? Is he taking Suzuki method?

Honestly, I think at 5th grade, just learning two instruments is a lot already. Especially if he's new to playing an instrument, I would not bring in theory stuff just now. It won't make sense to him until he's able to play an instrument well enough anyway. If you really want to do more theory, you might just ask the teacher to mix in a little more theory, or supplement with a few worksheets.

I took theory and ear training lessons privately in high school and it was totally worth it, it made me a much better musician. Of course I still wasn't that great. But it really helped. But-- I was in high school and self-motivated. I just think it's a lot to put on a 5th grader.

It depends on whether it's band or orchestra, and whether the person doing private lessons uses a curriculum or just a few workbooks.

My son gets a good amount in piano lessons. He's 9 and just started. It's the Harmony Road curriculum, which I had never heard of. It's the solfege method, and incorporates music theory in each lesson, in a spiraling pattern (introduction, repetition, building, etc.).

Do your kids study music theory? If so, is it part of instrumental lessons? My fifth grader is learning two instruments (one home; one school) but it doesn't seem like they get much theory. Do people still supplement on this? Does it ramp up later in school? Is it worth it?