Children in the military
It noted:

Clearly one of the most urgent priorities is to remove everyone under 18 years of age from armed forces.
Meanwhile, the UN Commission on Human Rights established a working group to negotiate a treaty to raise the legal standard. After a global campaign and complex negotiations, the new treaty was agreed in 2000 as the Optional Protocol to the convention on the Rights of the Child on the Involvement of Children in Armed Conflict. The treaty prohibited the direct participation of all children in armed conflict for the first time, while continuing to allow state armed forces (though not non-state armed groups) to recruit children from age 16. The protocol came into force on 12 February 2002.

Special Representative of the Secretary-General for Children and Armed Conflict: The Machel Report led to a new mandate for a Special Representative of the Secretary-General for Children and Armed Conflict (SRSG-CAAC). Among the tasks of the SRSG is to draft the Secretary-General's annual report on children and armed conflict, which lists and describes the worst situations of child recruitment and use from around the world.

Security Council: The United Nations Security Council convenes regularly to debate, receive reports, and pass resolutions under the heading "Children in armed conflict". The first resolution on the issue, Resolution 1261, was passed in 1999. In 2004 Resolution 1539 was passed unanimously, condemning the use of child soldiers and mandating the UN Secretary-General to establish a means of tracking and reporting on the practice, known as the Monitoring and Reporting Mechanism.

United Nations Secretary-General: The Secretary-General publishes an annual report on children and armed conflict. As of 2017, his report identified 14 countries where children were widely used by armed groups during 2016 (Afghanistan, Colombia, Central African Republic, Democratic Republic of the Congo, Iraq, Mali, Myanmar, Nigeria, Philippines, Somalia, South Sudan, Sudan, Syria, and Yemen) and six countries where state armed forces were using children in hostilities (Afghanistan, Myanmar, Somalia, Sudan, South Sudan, and Syria).

Children in the military today—by region and country: This section covers the use of children for military purposes today. For historical cases, see History of children in the military.

Africa: In 2003, the UN Office for the Coordination of Humanitarian Affairs estimated that up to half of children involved with state armed forces and non-state armed groups worldwide were in Africa. In 2004, Child Soldiers International estimated that 100,000 children were being used in state and non-state armed forces on the continent; and in 2008 an estimate put the total at 120,000 children, or 40 percent of the global total.
The African Charter on the Rights and Welfare of the Child (1990), which most African states have ratified, prohibits all military recruitment of children aged under 18. Nonetheless, according to the UN, in 2016 children were being used by armed groups in seven African countries (Central African Republic, Democratic Republic of the Congo, Mali, Nigeria, Somalia, South Sudan, Sudan) and by state armed forces in three (Somalia, Sudan, South Sudan).
International efforts to reduce the number of children in military organisations in Africa began with the Cape Town Principles and Best Practices, developed in 1997. The Principles proposed that African governments commit to OPAC, which was being negotiated at the time, and raise the minimum age for military recruitment from 15 to 18. The Principles also defined a child soldier to include any person under the age of 18 who is "part of any kind of regular or irregular armed force or group in any capacity ... including girls recruited for sexual purposes ..."
In 2007, the Free Children from War conference in Paris produced the Paris Principles, which refined and updated the Cape Town Principles, applied them globally, and outlined a practical approach to reintegrating current child soldiers.

Central African Republic: The use of children by armed groups in the Central African Republic has historically been common. Between 2012 and 2015 as many as 10,000 children were used by armed groups in the nationwide armed conflict and as of 2024 the problem persists nationwide with a most likely greater amount fighting now. The mainly Muslim Séléka coalition of armed groups and the predominantly Christian Anti-balaka militias have both used children in this way; some are as young as eight.
In May 2015 at the Forum de Bangui (a meeting of government, parliament, armed groups, civil society, and religious leaders), a number of armed groups agreed to demobilize thousands of children.
In 2016 a measure of stability returned to the Central African Republic and, according to the United Nations, 2,691 boys and 1,206 girls were officially separated from armed groups. Despite this, the recruitment and use of children for military purposes increased by approximately 50 percent over that year, mostly attributed to the Lord's Resistance Army.

Democratic Republic of the Congo: Thousands of children serve in the military of the Democratic Republic of the Congo (DRC) and various rebel militias. It has been estimated that more than 30,000 children were fighting with various parties to the conflict at the height of the Second Congo War. It was claimed in the film Kony 2012 that the Lord's Resistance Army recruited this number.
Currently, the DRC has one of the highest proportions of child soldiers in the world. The international court has passed judgment on these practices during the war. Thomas Lubanga Dyilo, one of the warlords in the DRC, has been sentenced to 14 years in prison because of his role in the recruitment of child soldiers between 2002 and 2003. Lubanga directed the Union of Congolese Patriots and its armed wing Patriotic Forces for the Liberation of Congo. The children were forced to fight in the armed conflict in Ituri.

Egypt: The minimum age to join the Egyptian military is 16. (CIA World Factsheet 2024)

Sao Tome and Principe: In the islands state of São Tomé and Príncipe, the minimum age for voluntary military service is 17 years old. (CIA World Factsheet 2024).

Somalia: A report published by the Child Soldiers International in 2004 estimated that 200,000 children had been recruited into the country's militias against their will since 1991. In 2017 UN Secretary-General António Guterres commented on a UN report which estimated that over 50 percent of Al-Shabaab's membership in the country was under the age of 18, with some as young as nine being sent to fight. The report verified that 6,163 children had been recruited in Somalia between 1 April 2010 and 31 July 2016, of which 230 were girls. Al-Shabaab accounted for seventy percent of this recruitment, and the Somali National Army was also recruiting children.

Sudan: In 2004 approximately 17,000 children were being used by the state armed forces and non-state armed groups. As many as 5,000 children were part of the main armed opposition group at the time, the Sudan People's Liberation Army (SPLA). Some former child soldiers were sentenced to death for crimes committed while they were soldiers.
In 2006, children were also recruited from refugee camps in Chad, and thousands were used in the conflict in Darfur. In 2005 the government ratified the OPAC treaty and by 2008 the military use of children had reduced in the country, but both state armed forces and the SPLA continued to recruit and use them. The use of children has continued to diminish, but in 2017 the UN was still receiving reports of children as young as 12 in government forces.

Uganda: "The LRA in Uganda became known mainly through the forced recruitment of thousands of children and adolescents who were trained as soldiers or forced to 'marry' members of the rebel group. Unlike all other, or earlier, rebel groups in Uganda, the LRA made the violent abduction or enslavement of children (preferably aged between twelve and fourteen) its main method of recruitment and concentrated its activities on attacking the civilian population."

Zimbabwe: In 2003, the Guardian reported multiple human rights violations by the National Youth Service, a state-sponsored youth militia in Zimbabwe. Originally conceived as a patriotic youth organisation, it became a paramilitary group of youth aged between 10 and 30, and was used to suppress dissent in the country. The organisation was finally banned in January 2018.

Americas: 

Barbados: Children can join the Barbados Army at 17 years and 9 months, with parental consent. (CIA Factsheet)

Bolivia: In 2001 the government of Bolivia acknowledged that male children as young as 14 may have been forcibly conscripted into the armed forces during recruitment sweeps. About 40% of the Bolivian army was believed to be under the age of 18, with half of those below the age of 16. As of 2018, Bolivia invites children to begin their adult conscription early, from age 17.

Brazil: In Brazil the local organized crime groups, such as Comando Vermelho, recruit children to sell drugs and commit homicides, as well as to fight with the police and other rival groups. Also the Brazilian militias recruit children to fight in the conflict against Comando Vermelho.

Canada: In Canada, people may join the reserve component of the Canadian Forces at age 16 with parental permission, and the regular component at 17 years of age, also with parental permission. They may not volunteer for a tour of duty until reaching age 18.