Introduction
How is the Military in Yemen and how does it work to maintain Sucity and fight terrorism? In terms of Military and security forces, we have the Republic of Yemen Government (ROYG) forces:

Ministry of Defense: Yemeni National Army, Air Force and Air Defense, Navy and Coastal Defense Forces, Border Guard, Strategic Reserve Forces (includes Special Forces and Presidential Protection Brigades, which are under the Ministry of Defense but responsible to the president), Popular Committee Forces (aka Popular Resistance Forces; government-backed tribal militia)

Ministry of Interior: Special Security Forces (paramilitary; formerly known as Central Security Forces), Political Security Organization (state security), National Security Bureau (intelligence), Counterterrorism Unit

Saudi-backed forces: paramilitary/militia border security brigades based largely on tribal or regional affiliation (based along the Saudi-Yemen border)

United Arab Emirates-backed forces include tribal and regionally based militia and paramilitary forces (concentrated in the southern governates): Southern Transitional Council (STC) forces, including the Security Belt Forces, the Shabwani and Hadrami “Elite” Forces, the Support and Backup Forces (aka Logistics and Support Forces), Facilities Protection Forces, and Anti-Terrorism Forces; Republican Forces; Joint Forces

Houthi (aka Ansarallah) forces: land, aerospace (air, missile), naval/coastal defense, presidential protection, special operations, internal security, and militia/tribal auxiliary forces (2023).
In Yemen, government forces under the Yemeni Ministry of Defense are responsible for territorial defense, but also have internal security functions; their main focus has been the Houthi separatists and protecting Yemen’s maritime borders, which are susceptible to smuggling of arms, fighters, and other material support for the Houthis and terrorist groups operating in Yemen, including al-Qa’ida in the Arabian Peninsula (AQAP) and the Islamic State of Iraq and ash-Sham in Yemen (ISIS-Yemen)

in 2015, a Saudi-led coalition of Arab states (UAE, Qatar, Bahrain, Morocco, Sudan, Kuwait, Jordan and Egypt) intervened militarily in Yemen in support of the Republic of Yemen Government (ROYG) against the separatist Houthis; Saudi military forces conducted operations in Yemen and raised and equipped paramilitary/militia security forces in Yemen based largely on tribal or regional affiliation to deploy along the Saudi-Yemen border; UAE's participation in 2015 included several thousand ground troops, as well as supporting air and naval forces; UAE withdrew its main military force from Yemen in 2019, but has retained a smaller military presence while working with proxies in southern Yemen, most notably the Southern Transitional Council (STC); UAE has recruited, trained, and equipped tens of thousands of Yemeni fighters and formed them into dozens of militia and paramilitary units

in 2022, the RYOG and the Houthis signed a truce, halting military operations and establishing humanitarian measures; the former front lines of conflict, in some areas mirroring Yemen’s pre -unification borders, remain static; AQAP and ISIS-Yemen have remained active in remote areas 

in January 2024, the US Government designated the Houthis (aka Ansarallah) as a Specially Designated Global Terrorist group; the designation came after the Houthis began launching attacks against international maritime vessels in the Red Sea and Gulf of Aden, as well as military forces positioned in the area to defend the safety and security of commercial shipping (2024)
Security and military information of Yemen
Military and security service personnel strengths information limited and widely varied; Yemen Government: up to 300,000 estimated military, paramilitary, militia, and other security forces; UAE- and Saudi-backed forces: estimated 150-200,000 trained militia and paramilitary fighters; Houthis: up to 200,000 estimated fighters (2022)
Military equipment inventories and acquisitions the inventory of the Yemeni Government forces consists primarily of Russian and Soviet-era equipment, although much of it has been lost in the current conflict; since the start of the civil war in 2014, it has received limited amounts of donated equipment from some Gulf States, including Saudi Arabia and UAE, as well as the US

Houthi forces are armed largely with weapons seized from Yemeni Government forces; they are also reported to have received military hardware from Iran (2023)
Military service age and obligation 18 is the legal minimum age for voluntary military service; conscription abolished in 2001; 2-year service obligation (note - limited information since the start of the civil war in 2014) (2022). note: as late as 2022, all parties to the ongoing conflict were implicated in child soldier recruitment and use; during the beginning of the truce in April 2022, the Houthis signed a plan with the UN to end the recruitment and use of child soldiers; Houthi leaders previously pledged to end the use of child soldiers in 2012, as did the Government of Yemen in 2014 
Military deployments .
Terrorism
In Yemen, the different Terrorist group(s) inlcude: Islamic Revolutionary Guard Corps (IRGC)/Qods Force; Islamic State of Iraq and ash-Sham - Yemen; al-Qa'ida in the Arabian Peninsula (AQAP), Hizballah
All Important Facts about Yemen

Want to know more about Yemen? Check all different factbooks for Yemen below.

Yemen is found in Western Asia