A common mistake in spoken English is to say ‘between you and I’, as in this sentence:
✗ It’s a tiny bit boring, between you and I.
In standard English, it’s grammatically correct to say ‘between you and me’ and incorrect to say ‘between you and I’. The reason for this is that a preposition such as between should be followed by an objective pronoun (such as me, him, her, and us) rather than a subjective pronoun (such as I, he, she, and we). Saying ‘between you and I’ is grammatically equivalent to saying ‘between him and she’, or ‘between we’, which are both clearly wrong. See More . . .