Allied Command Operations (ACO) is one of NATO's two strategic military commands, the other being Allied Command Transformation (ACT). Located at Supreme Headquarters Allied Powers Europe (SHAPE), near Mons, Belgium, it is responsible for all Alliance operations wherever it may be required.

At the NATO Summit in Lisbon in November 2010, Allied Heads of State and Government agreed to a framework for a new NATO Command Structure (NCS), including the new ACO structure.
Strategic level
The command structure is based on functionality rather than geography. There are three tiers of command: strategic, operational, and the tactical or component level.
At the strategic level, Allied Command Operations is commanded by Supreme Allied Commander Europe (SACEUR). SACEUR is dual-hatted as the commander of the US European Command, which shares many of the same geographical responsibilities.

Operational level

The operational level consists of two standing Joint Force Commands (JFCs): one in Brunssum, the Netherlands, and one in Naples, Italy. Both have to be prepared to conduct comprehensive operational-level campaign planning and deploy into a theatre as a Deployed Joint HQ (DJHQ). They have to be prepared for any NATO operation up to a Major Joint Operation (MJO) for a period of up to one year, including provision of the core elements of a Joint Multinational Logistic Support Group (JLSG).

Commands at this level are also responsible for engaging key partners and regional organisations in order to support regional NATO HQ engagement, as directed by SACEUR, and support the reinforcement of cooperation with operational partners and prepare partner countries for NATO membership.

Component or tactical level

Headquarters Allied Land Command (HQ LANDCOM) is established in Izmir (Turkey) to provide a deployable land command and control capability of which the principal responsibility is to provide a core Land Component Command HQ (LCC HQ) for a joint operation larger than an MJO in support of a Joint Force Headquarters. This land HQ can also be used to provide the core of an LCC HQ for a joint operation up to an MJO in size or deployable C2 capability for a land operation. HQ LANDCOM is responsible for the planning, conduct and direction of land operations in support of a Joint Force Command Headquarters and as the principal land advisor for the Alliance it provides land competency and contributes to development, transformation, engagement and outreach within its domain of expertise.
Additionally, Land Command provides expertise in support of Alliance land forces readiness, competency and standardization, including their evaluation and certification; delivers a planning capability in support of Higher HQs and the NATO Force Structure; when directed by SACEUR, provides the core of the HQ responsible for the conduct of land operations and the synchronization of land forces C2 in accordance with the Allied Level of Ambition.
Headquarters Allied Maritime Command (HQ MARCOM) is established in Northwood (United Kingdom), to provide C2 for the full spectrum of joint maritime operations and tasks. From its static location, it plans, conducts, and supports joint maritime operations. HQ MARCOM is responsible for maritime competency and acts as NATO's principal maritime advisor. It maintains comprehensive situational awareness throughout the maritime environment, and is ready to command a maritime heavy SJO or act as the Maritime Component Commander (MCC) to support up to a MJO+. This HQ contributes to development and transformation, engagement and outreach within its domain of expertise.
Headquarters Allied Air Command (HQ AIRCOM) is established inRamstein (Germany) for the planning and direction of the air component of Alliance operations and missions, execution of Alliance air and missile defence operations and missions, including the standing air defence missions and missile defence, as well as enabling supporting functions, including back-up capability for the CAOCs. HQ AIRCOM includes the core of a NATO Joint Forces Air Component (JFAC) that, with adequate supplementation from within NCS and augmentation from outside the NCS, can provide C2 for up to an air heavy SJO or can act as Air Component Command (ACC) to support up to a MJO+. HQ AIRCOM provides air competency and as the principal air advisor for the Alliance, it contributes to development and transformation, engagement and outreach within its domain of expertise.
Tactical Air C2 elements:
a. Two CAOCs are located at Uedem (Germany) and Torrejon (Spain). CAOCs are hybrid entities that consist of two parts: a Static Air Defence Centre (SADC) and a Deployable Air Operations Centre (D-AOC).
b. The Deployable Air Command and Control Centre (DACCC), located at Poggio Renatico (Italy), is a hybrid entity which consists of three elements: a Deployable Air Control Centre – Recognized Air Picture Production Centre – Sensor Fusion Post (DARS), a D-AOC and a Deployable Sensors Suite (DSS). In peacetime, the DACCC will be responsible for the initial functional training of assigned NCS JFAC personnel from both the HQ AIRCOM and the D-AOCs.
The NATO CIS Group  

Additionally, there will be a NATO CIS Group based in Mons, Belgium that will provide deployable communications and information systems support for ACO. The NATO CIS Group is responsible for the provision of all deployable CIS capabilities, as well as CIS operations and exercises planning and control. It will be supported by three NATO Signals Battalions located at Wesel, Germany, Grazzanise, Italy, and Bydgoszcz, Poland; these three will be complemented by various smaller elements (Deployable CIS modules) elsewhere. The functions of this group may evolve once the Communications and Information Agency is set up.


Lastly, Striking Force NATO (STRIKFORNATO), which focuses on maritime operations, has been moved from Italy to Portugal. And final agreement from the North Atlantic Council is awaited for the NATO Airborne Early Warning and Control Force (NAEW&CF) and Alliance Ground Surveillance (AGS).