It seems to have become increasingly fashionable for persons to say, “Between you and I.” This is wrong. It is a basic rule of grammar that a preposition is always followed by the accusative, never the nominative. One has simply to transpose the pronouns to realise how incorrect it is: “Between I and you.” {{more}}
Other examples also illustrate the incorrectness: “Between we and she;” “He spoke to I and she;” “Give it to I.” I could go on and on, but these simple examples should suffice.
Let me quote from The Collins Dictionary, as it defines the word “between”: “Confined or restricted to: between you and me”…
Grammatically, between you and I is incorrect. The proper construction is “Between you and me.”
I hope this clarifies a simple matter of grammar, which has been embarrassing me as I have listened to so many public speakers confide, “Between you and I.”

A Cecil Cyrus