A butler is a person who works in a house serving and is a domestic worker in a large household. In great houses, the household is sometimes divided into departments with the butler in charge of the dining room, wine cellar, and pantry. Some also have charge of the entire parlour floor and housekeepers caring for the entire house and its appearance. A butler is usually male and in charge of male servants while a housekeeper is usually a woman and in charge of female servants. Traditionally, male servants (such as footmen) were better paid and of higher status than female servants. The butler, as the senior male servant, has the highest servant status. He can also sometimes function as a chauffeur.

In older houses where the butler is the most senior worker, titles such as majordomo, butler administrator, house manager, manservant, staff manager, chief of staff, staff captain, estate manager, and head of household staff are sometimes given. The precise duties of the employee will vary to some extent in line with the title given, but perhaps, more importantly in line with the requirements of the individual employer. In the grandest homes or when the employer owns more than one residence, there is sometimes an estate manager of higher rank than the butler. The butler can also be assisted by a head footman or footboy called the under-butler.