The Aug. 19 letter from ACLU attorney William Sharp says districts that don't abide by the guidelines will face court challenges.
He said Gideons International has handed out Bibles in elementary schools as recently as last year despite past warnings from the ACLU.
Sharp told the Lexington Herald-Leader that the intent of the letter was to encourage districts to follow federal guidelines and stay out of court.
Logan County Superintendent Marshall Kemp says Gideons have handed out Bibles there in the past, but probably won't be allowed to do so anymore.