The Whiteboys, a secret Irish agrarian organisation in 18th-century Ireland which uses violent tactics to defend tenant farmer land rights for subsistence farming, is created on October 1, 1761. Their name derives from the white smocks the members wear in their nightly raids. They seek to address rack-rents, tithe collection, excessive priests’ dues, evictions and other oppressive acts. As a result they target landlords and tithe collectors. Over time, Whiteboyism becomes a general term for rural violence connected to secret societies. Because of this generalisation, the historical record for the Whiteboys as a specific organisation is unclear. There are three major outbreaks of Whiteboyism: 1761–64, 1770–76 and 1784–86.

Between 1735 and 1760 there is an increase in land used for grazing and beef cattle, in part because pasture land is exempt from tithes. The landlords, having let their lands far above their value, on condition of allowing the tenants the use of certain commons, now enclose the commons, but do not lessen the rent. As more landlords and farmers switch to raising cattle, labourers and small tenant farmers are forced off the land. The Whiteboys develop as a secret oath-bound society among the peasantry. Whiteboy disturbances had occurred prior to 1761 but were largely restricted to isolated areas and local grievances, so that the response of local authorities had been limited.

Their operations are chiefly in the counties of Waterford, Cork, Limerick, and Tipperary. This combination is not political. It is not directed against the government, but against the local landlords. Members of different religious affiliations take part.

The first major outbreak occurs in County Limerick in November 1761 and quickly spreads to counties Tipperary, Cork, and Waterford. A great deal of organisation and planning seems to have gone into the outbreak, including the holding of regular assemblies. Initial activities are limited to specific grievances and the tactics used non-violent, such as the levelling of ditches that closed off common grazing land, although cattle hamstringing is often practised as the demand for beef prompts large landowners to initiate the process of enclosure. As their numbers increase, the scope of Whiteboy activities begins to widen, and proclamations are clandestinely posted stipulating demands such as that rent not be paid, that land with expired leases not be rented until it has lain fallow for three years, and that no one pay or collect tithes demanded by the Anglican Church. Threatening letters are also sent to debt collectors, landlords, and occupants of land gained from eviction, demanding that they give up their farms.

March 1762 sees a further escalation of Whiteboy activities, with marches in military array preceded by the music of bagpipes or the sounding of horns. At Cappoquin they fire guns and march by the military barracks playing the Jacobite tune “The lad with the white cockade.” These processions are often preceded by notices saying that Queen Sive and her children will make a procession through part of her domain and demand that the townspeople illuminate their houses and provide their horses, ready saddled, for their use. More militant activities often follow such processions with unlit houses in Lismore attacked, prisoners released in an attack on Tallow jail and similar shows of strength in Youghal.

The events of March 1762, however, prompt a more determined response, and a considerable military force under Charles Moore, 1st Marquess of Drogheda is sent to Munster to crush the Whiteboys.

On April 2, 1762 a force of 50 militia men and 40 soldiers set out for Tallow. By mid-April at least 150 suspected Whiteboys have been arrested. Clogheen in County Tipperary bears the initial brunt of this assault as the local parish priest, Fr. Nicholas Sheehy, had earlier spoken out against tithes and collected funds for the defence of parishioners charged with rioting. An unknown number of “insurgents” are reported killed in the “pacification exercise” and Fr. Sheehy is unsuccessfully indicted for sedition several times before eventually being found guilty of a charge of accessory to murder, and hanged, drawn and quartered in Clonmel in March 1766.

In the cities, suspected Whiteboy sympathisers are arrested and in Cork, citizens form an association of about 2,000 strong which offer rewards of £300 for capture of the chief Whiteboy and £50 for the first five sub-chiefs arrested. They often accompany the military on their rampages. The leading Catholics in Cork also offer similar rewards of £200 and £40 respectively.

Acts passed by the Parliament of Ireland (to 1800) and Parliament of the United Kingdom of Great Britain and Ireland (from 1801) to empower the authorities to combat Whiteboyism are commonly called “Whiteboy Acts.”