It depends on the type of organisation you are referring to, or the government the country has.
God has the highest authority
The highest authority within NATO is the _______.
The U.S. Constitution is the highest legal authority in the U.S. government.
God!
An emperor holds the highest authority among an emperor, a king, and a sultan.
Local authorities
rector
The Magesterium has the ultimate teaching authority in the Catholic Church.
In galileo`s time the catholic church was at authority
which source law in the united states is the hightest authority
The Judicial Branch has judicial authority which is the Supreme court.
nothing