The Saudi military numbers 227,000 troops, including 75,000 in the army, 13,500 in the navy and 20,000 in the air force.
Some 16,000 personnel are committed to air defences, 2,500 responsible for strategic missiles and 100,000 man the National Guard, according to the IISS Military Balance, 2015.
The kingdom also has 24,500 paramilitary forces.
The Saudi armed forces have close ties with foreign armies, particularly the United States, Britain and France which gives them access to training and equipment.
The Saudi army regularly buys modern equipment, with the navy seeking to purchase submarines, according to the media.
Riyadh's appetite for arms, already high due to a perceived threat from Iran, is fed by regional instability, notably in Yemen, where Saudi Arabia on Thursday launched air strikes as part of a multinational coalition.
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It is traditionally a customer of the US and British arms industries, although Riyadh has also sealed contracts with France and Germany for its navy and has bought Eurofighter jets.
The Saudi army has 600 heavy tanks, 780 light armoured vehicles and 1,423 armoured troop carriers.
Its air force is equipped with 313 fighter jets, including F-15s, Tornados and Eurofighter Typhoons, as well as helicopters.
Considered a priority, air defences and deterrents include 16 batteries of Patriot missiles, 17 batteries of Shahine missiles, 16 of Hawk missiles and 73 Crotale/Shahine missile units.
The National Guard is an autonomous force under its own ministry and plays a role both in internal security and conventional defence.
Mainly a mechanised force, it includes a large, tribal-based militia.
Modernisation plans include orders for AT missiles, wheeled AFVs and CAESAR artillery. It is forming its own air wing with confirmed orders for US-built AH6i, Apache and Black Hawk helicopters.