The war in Sri Lanka is primarily fought between the Army and the LTTE, with some other groups joining the battle until being wiped out by either of the first two groups.

The Army in Sri Lanka is a large conventional force with a strong infantry base. Some 40,000 people serve in the Army, although this may have increased through repeated calls for enlistment by the regime. They are organized into 5 infantry brigades, 2 reconnaissance regiments, and 5 support regiments. Infantry weapons are mainly the AK-47 assault rifle, Bren L4 machinegun, and the M2HB heavy machinegun although other weapons can be found in service. Artillery support is provided by several small-calibre howitzers including the 25 Pounder, the 85mm Type-56, and the 76mm M-48 and this is supplemented by a small number of 106mm M-40 and 82mm M-60 recoilless launchers. Mortars include the Soviet 82mm M-37, 107mm M-38, and the 120mm M-43. Finally, Armoured units have a number of wheeled AFVs, including Saladins, Ferrets, Dingos, BTR-152s, and armoured SAMIL 100s. 

Small local militia or Home Guard units provide support for the military and attempt to keep local peace along with police forces. Both the militia and police use civilian small arms, but the police may have access to military-style weapons. There also exist paramilitary Special Task Force Units, which seem to be internal security forces.

On the opposing side are the LTTE. Little is known of their structure or armaments, but they may follow a Soviet-style organization as all Sri Lankan guerrilla groups have received training either from the Palestinians in Lebanon or the Indian government. The LTTE is also believed to have received weapons from the Indian government and possibly other Marxist nations. So, speculation on likely arms for the LTTE would produce a list encompassing AK-47s and older model Soviet support weapons such as RP-46 and RPD machineguns. Photographs have also shown them fielding L7A2 GPMGs. Weapons such as DShKs and RPG-7Vs are also likely to be found, but would be rare. Rounding out the LTTE armouries would be large quantities of civilian and military rifles, pistols, and shotguns.

Other Tamil guerrilla groups would mimic the LTTE in weapons, but not numbers. The LTTE is large enough to have held off both the Sri Lankan Army and the Indian Peace Keeping Force (IPKF) while at the same time fighting the other Tamil groups to eliminate rivals. On several occasions, the LTTE has almost wiped out its rivals. These other Tamil groups include the LTTE-allied Eelam Revolutionary Organization (EROS), a terrorist group and the Three Star Group, which is a rival to the LTTE. The Three Star Group consists of the Eelam People's Revolutionary  Liber­ation Front (EPRLF), the People's Liberation Organization of Tamil Eelam (PLOT), and the Tamil Eelam Liberation Organization (TELO).

The final guerrilla group is the Sinhalese Janatha Vinukthi Peramuna (JVP), or People's Liberation Front. These are Marxist insurgents who are fighting against the government which they see as having given too many concessions to the Tamils. Their weapons likely mirror the LTTE.

Of these last groups, only the LTTE currently remains a viable guerrilla organization. The others have been either wiped out by counterinsurgency efforts of the government or by LTTE attacks. Those fragments which remain have chosen terrorist tactics to continue their struggle.