In a message marking Eid al-Fitr, the festival which ends the holy month of Ramadan, King Fahd and Crown Prince Abd Allah said the recent bombings had no basis in Islam and called on Muslims to "work together to combat the roots of deviation".
The blunt appeal reflected the high-level concern over security in the kingdom after suspected al-Qaida bombers killed at least 18 people in a Riyadh residential compound on 9 November. Some analysts fear further attacks over the Eid holiday.
In Muslim Turkey, more than 50 people were killed in suicide blasts that hit Istanbul on 15 and 20 November.
"A true Muslim does not carry out corruption on earth and does not seek destruction," the Saudi royals said in a statement carried by the state news agency SPA.
"Islam is innocent of the terrorist acts which took place here and elsewhere by groups claiming to be Muslims and which are a result of mistaken beliefs and deviant behaviour."
Saudi Arabia, the birthplace of al-Qaida leader Osama bin Laden and 15 of the alleged 19 hijackers who flew planes into US targets on 11 September two years ago, has cracked down heavily on militants since a triple bombing in Riyadh in May killed 35 people.
It vowed to hit with an "iron fist" those behind the November attack. Visitors to Makka have reported tight military security on roads leading into Islam's holy city and high police presence on its streets.
The security measures have been backed up by a television campaign to eliminate support for armed dissidents in the kingdom.