Baron Rathdonnell, of Rathdonnell in the County of Donegal, is a title in the Peerage of Ireland. It was created on 21 December 1868 for John McClintock, with remainder to the male issue of his deceased younger brother Captain William McClintock-Bunbury (who had represented County Carlow in the House of Commons). The barony is named after the townland of Rathdonnell, near the village of Trentagh, just north-west of Letterkenny.
The barony of Rathdonnell was the second-last barony created in the Peerage of Ireland. Lord Rathdonnell was succeeded according to the special remainder by his nephew, the second Baron, who sat in the House of Lords as an Irish representative peer from 1889 to 1929 and also served as Lord Lieutenant of County Carlow between 1890 and 1922. the title is held by the fifth Baron, the second Baron's great-grandson, who succeeded his father in 1959.
The Arctic explorer, Admiral Sir Francis McClintock, was the nephew of the first Baron.
The family seat is Lisnavagh House, near Rathvilly, County Carlow.
The heir apparent is the present holder's son, the Hon. William Leopold McClintock-Bunbury (born 1966).
The heir-in-line is his son, Thomas Anthony McClintock-Bunbury (born 2011).
| Escutcheon: | Per pale Gules and Azure a chevron Ermine between three escallop shells Argent. |
| Crest: | A lion passant Proper. |
| Supporters: | Dexter a lion and sinister a leopard both Proper each gorged with a collar Ermine and each charged on the shoulder with an escallop Argent. |
| Motto: | Virtute Et Labore [2] |