Hi,
I am new to the forum, I have a son who is working towards the Grade 5 theory, and has recently sat
for the Grade 3 exam.( when is the results going to come in???- his teacher said 6-8 weeks!!!)
My question is : once you have passed Grade 5, do you have to sit for Grade 8 theory ? I suspect you have to do this if you are going to continue on the music route to a Music Diploma?

Thanks, all your answers will be apreciated.

Theory results can take usually 4 - 6 weeks. To the best of my knowlege, gade 6 theory or practical musicianship is the prerequisite for diploma. I don't know of any diploma which requires grade 8 theory.

Results should be in soon!
DipABRSM only needs Grade 6 as a prerequisite. Grade 8 would be useful he was looking to go on to Uni to study music.

Grade 6 theory is indeed required for DipABRSM 'Teaching', and as you can see from the prerequisites below....

LRSM (Instrumental/Vocal Teaching)
DipABRSM (Principles of Instrumental/Vocal Teaching) in the instrument taught or a
permitted substitution (see p. 23), and ABRSM Grade 8 Theory (1992 syllabus) or a
permitted substitution.

so Grade 8 Theory is needed for LRSM 'Teaching'

To clarify:

For performance diplomas with the ABRSM, you need a grade 8, for which you need grade 5 theory.

For teaching diplomas you need theory prerequisites as well - grade 6 theory for DipABRSM, grade 8 theory for LRSM>

Practical Musicianship or, for grade 5, Jazz can be used instead of theory as the prerequisite.

You don't say how old your son is. While it is completely not a pre-requisite, it is very helpful to a student to be able to work at about Grade 6 level theory when doing AS and A2 Music. Of course the opposite applies I think too - if you are working well on your musical literacy at AS level than grade 6 theory will be that much easier to do. (But there's no "have to" about it!)