A sole proprietorship, or simply proprietorship, is a type of business entity which legally has no separate existence from its owner. Hence, the limitations of liability enjoyed by a corporation and limited liability partnerships do not apply to sole proprietors. All debts of the business are debts of the owner. It is a "sole" proprietor in the sense that the owner has no partners. A sole proprietorship essentially means a person does business in his or her own name and there is only one owner. A sole proprietorship is not a corporation; it does not pay corporate taxes, but rather the person who organized the business pays personal income taxes on the profits made, making accounting much simpler. A sole proprietorship need not worry about double taxation like a corporate entity would have to.

Most sole proprietors will register a trade name or "Doing Business As". This allows the proprietor to do business with a name other than his or her legal name and also allows the proprietor to open a business account with banking institutions.