The first known inhabitants of the Dublin region were hunter-gatherers living during the Middle Stone Age, around 5500 BC.

The first farmers appeared shortly after 4000 BC. Evidence of their culture survives in the burial cairns, passage tombs, portal tombs and wedge tombs in the Dublin Mountains and on the coastal lowlands. Archaeological excavations have uncovered prehistoric copper axe-heads, bronze and gold artifacts, and iron age items.  The existence of ringforts or ráthsmay be deduced from the names of several of the modern city's suburbs: Rathmines, Rathgar, Rathfarnham etc

When contemporary records began in the 5th century, there was a thriving community of farmers and fishermen in existence in the vicinity of Cornmarket and High Street.

The two early settlements were called “Ath Cliath” and Duiblinn. The Viking settlement of about 841 was known as Dyflin, from the Irish Duiblinn ("black pool"), which also led to the modern English name.

The Vikings ruled Dublin for almost three centuries. Viking Dublin was a major slave center. Although they were expelled in 902 and defeated by King Brian Boru at the Battle of Clontarf in 1014, Viking rule of Dublin would not end completely until 1171 when the city was captured by the Anglo-Normans.

Dublin became the center of English power in Ireland after the Norman invasion of the southern half of Ireland in 1169–71, replacing Tara as the focal point of Ireland's polity.

County Dublin was the first county in Ireland to be shired in the 1190s, and the city became the capital of the English Lordship of Ireland. Dublin was peopled extensively with settlers from England and Wales.   English rule was centered on Dublin Castle. Dublin was also the main seat of the Parliament of Ireland from 1297 to1800.

Medieval Dublin had a population of around 5,000 to 10,000 people. Outside the city walls were suburbs such as the Liberties, and Irishtown, where Gaelic Irish were supposed to live, having been expelled from the city.

Throughout the Middle Ages, the city paid "black rent" to the neighboring Irish clans to avoid their predatory raids. Dublin and its inhabitants were transformed by the upheavals of the 16th and 17th centuries in Ireland.

Protestants became a majority in Dublin in the 1640s. In the 1650s after the Cromwellian conquest of Ireland, Catholics were banned from dwelling within the city limits.

The United Irishmen planned to take Dublin in a street rising in 1798, but their leaders were arrested, and the city occupied by a large British military presence. Following failed Risings in 1803, 1848 and 1867 the Easter Rebellion began in Dublin in 1916. While the rebellion failed the fight for independence continued. Following success in the 1918 elections the First Dail met in the Mansion House and proclaimed the Irish Republic.