An Garda Síochána (Irish pronunciation: [ənˠ ˈɡaːɾˠd̪ˠə ˈʃiːxaːn̪ˠə] ^ⓘ; meaning "the Guardian(s) of the Peace") is the national police and security service of the Republic of Ireland. It is more commonly referred to as the Gardaí (pronounced [ˈɡaːɾˠd̪ˠiː]; "Guardians") or "the Guards". The service is headed by the Garda Commissioner, who is appointed by the Irish Government. Its headquarters are in Dublin's Phoenix Park.

Since the formation of the Garda Síochána in 1923, it has been a predominantly unarmed force, and more than three-quarters of the service do not routinely carry firearms. As of June 2025, the police service had 14,525 sworn members (including 302 sworn Reserve members) and 3,669 civilian staff. Operationally, the Garda Síochána is organised into four geographical regions: the East, North/West, South and Dublin Metropolitan regions, in turn broken into divisions, districts and sub-districts.

The service is the main law enforcement and security agency in the state, acting at local and national levels. Its roles include crime detection and prevention, drug enforcement, road traffic enforcement and accident investigation, diplomatic and witness protection responsibilities; it also provides a community policing service. Special units exist for specific areas of work such as organised crime prevention, migration management and cyber crime, and there is a central Garda technical bureau, a mounted unit and a canine unit. The service has its own college.

Members of the Garda Síochána are not free to join general trade unions but are represented by four rank-based organisations; there is also an association for retired members of the force.

The service was originally named the Civic Guard in English, but in 1923 it became the Garda Síochána in both English and Irish. In 2025, its title was altered to An Garda Síochána. This is usually translated as "the Guardians of the Peace". Garda Síochána na hÉireann ("of Ireland", pronounced [ˈɡaːɾˠd̪ə ˈʃiːxaːn̪ˠə n̪ˠə ˈheːɾʲən̪ˠ]) appears on its logo but is seldom used elsewhere. At that time, there was a vogue for naming the new institutions of the Irish Free State after counterparts in the French Third Republic; the term "guardians of the peace" (gardiens de la paix) had been used since 1870 in French-speaking countries to designate civilian police forces as distinguished from the armed gendarmery, notably municipal police in France, communal guards in Belgium and cantonal police in Switzerland.

How it is referred to depends on the register being used. It is variously known as An Garda Síochána; the Garda Síochána; the Garda; the Gardaí (plural); and it is popularly called "the Guards". Although Garda is singular, in these terms it is used as a collective noun, like police.

An individual officer is called a garda (plural gardaí), or less formally, a "guard", and is typically addressed as such by members of the public when on duty. A police station is called a garda station. Garda is also the name of the lowest rank within the force (e.g. "Garda John Murphy", analogous to the British term "constable" or the American "officer", "deputy", "trooper", etc.). A female officer was once officially referred to as a bangharda (pronounced [ˈbˠanˠˌɣaːɾˠd̪ˠə]; "female guard"; plural banghardaí). This term was abolished in 1990, but is still used colloquially in place of the gender-neutral garda.

Colloquially, as a slang or derogatory term, they are sometimes referred to in certain areas of Ireland as "the shades".