Kelleher, and its variants Keliher, Kellaher etc., are the English versions of the Irish name O Ceileachair, from ceileachar, meaning "uxorious" "overly fond of one's wife",. The original Ceileachair from whom the family claim descent was a nephew of Brian Boru, and part of the famous Dal gCais tribal grouping. Although the family originated in Clare, homeland of the Dal gCais, they migrated south-east to Co. Cork in the fourteenth century and it is now in that county and the adjoining Co. Kerry that the surname is most frequently found. It is sometimes abbreviated to "Keller", a name more usually associated with Germany, and in this form is recorded in Co. Cork.