The House of Orléans (French: Maison d'Orléans), sometimes called the House of Bourbon-Orléans (French: Maison de Bourbon-Orléans) to distinguish it, is the fourth holder of a surname previously used by several branches of the Royal House of France, all descended in the legitimate male line from the dynasty's founder, Hugh Capet. The house was founded by Philippe I, Duke of Orléans, younger son of Louis XIII and younger brother of Louis XIV, the "Sun King".

From 1709 until the French Revolution, the Orléans dukes were next in the order of succession to the French throne after members of the senior branch of the House of Bourbon, descended from Louis XIV. Although Louis XIV's direct descendants retained the throne, his brother Philippe's descendants flourished until the end of the French monarchy. The Orléanists held the French throne from 1830 to 1848 and are still pretenders to the French throne today.

The House of Orléans has a cadet branch in the House of Orléans-Braganza, founded with the marriage between Isabel of Braganza, Princess Imperial of Brazil, and Prince Gaston of Orléans, Count of Eu. Although never reigning, the House of Orléans-Braganza has claimed the Brazilian throne since 1921.

It became a tradition during France's ancien régime for the Duchy of Orléans to be granted as an appanage to a younger (usually the second surviving) son of the king. While each of the Orléans branches thus descended from a junior prince, they were always among the king's nearest relations in the male line, sometimes aspiring to the throne itself, and sometimes succeeding. Since they had contemporaneous living descendants, there were two Bourbon-Orléans branches at court during the reign of Louis XIV. The elder of these branches consisted of Prince Gaston, Duke of Anjou, younger son of king Henry IV, and the four daughters of his two marriages.

Prince Gaston became the Duke of Orléans in 1626, and held that title until his death in 1660. Upon the death of Gaston, the appanage of the Duchy of Orléans reverted to the Crown. His nephew, Louis XIV, then gave Gaston's appanages to his younger brother Prince Philippe, who became Duke of Orléans. At court, Gaston was known as Le Grand Monsieur ("The Big Milord"), and Philippe was called Le Petit Monsieur ("The Little Milord") while both princes were alive.

Philippe and his second wife, the famous court writer Elizabeth Charlotte of the Palatinate, founded the modern House of Bourbon-Orléans. Before then, Philippe had been styled as the Duke of Anjou, like Prince Gaston. Besides receiving the appanage of Orléans, he also received the duchies of Valois and Chartres: Duke of Chartres became the courtesy title by which the heirs apparent of the Dukes of Orléans were known during their fathers' lifetimes. Until the birth of the king's son, the Dauphin Louis, the Duke of Orléans was the heir presumptive to the crown. He was to maintain a high position at court till his death in 1701.

Their surviving son, Philippe II served as the regent of France for the young Louis XV. As a fils de France, Philippe's surname was de France. Upon his death, his son inherited the Orléans dukedom, but as a petit-fils de France. His surname d'Orléans (used also by his descendants) was taken from his father's main title. The first two dukes, as son and patrilineal grandson, respectively, of a French king, were entitled to be addressed as Royal Highness. But Philippe I was primarily known as Monsieur, the style reserved at the French court for the king's eldest brother.

Philippe II was succeeded as duke by his only legitimate son, Louis d'Orléans, who was entitled to the style of Serene Highness as a prince du sang. After 1709, the heads of the Orléans branch of the House of Bourbon ranked as the premier princes du sang – this meant that the dukes could be addressed as Monsieur le Prince (a style they did not, however, use). More importantly, should there be no heir to the Crown of France in the king's immediate family, then the Orléans family would ascend by right the throne.