The Vigo County School Corporation in Terre Haute, Indiana, is telling teachers and other staff they can't lead prayers during school-sponsored events.
A letter from the school district's attorney said all of the district's principals have been told "that teacher-led prayer with students present will cease, as it is prohibited by the Constitution and should not be allowed."
The move comes after the Freedom From Religion Foundation filed a complaint against the district in May after a teacher opened an awards banquet with prayer.
The group said public school teachers must be religiously neutral while at work.
Meanwhile, Superintendent Dan Tanoos said he'll "continue to allow student-led prayer when they choose to do so."