Brandon Jones and Tommy Coleman filed suit last year, claiming the invocation of Jesus' name before meetings violates the establishment clause of the First Amendment.
When a federal judge denied their request to stop the prayers until the lawsuit is decided, Jones and Coleman appealed.
On Friday, the 6th Circuit ruled that Hamilton County's written prayer policy is constitutional on its face because it "aims to respect the diversity of all religious groups."
The policy could still be ruled unconstitutional if the record shows the actual prayers spoken promote Christianity over other faiths.
The Kentucky League of Cities filed a brief in the case since any 6th Circuit ruling affects Kentucky municipalities.