Do I need an MOI certificate for an IELTS waiver for a UK MBA?

Yes, many UK universities will accept a Medium of Instruction (MOI) certificate as an alternative to IELTS for MBA admissions. Since your studies were in English and you have excellent grades, you are a strong candidate for this option. However, requirements vary by university, so be sure to check with each one to confirm if an MOI is accepted and if extra proof, like Class 12 English marks, is also needed.