Chirayu Isarangkun Na Ayuthaya (จิรายุ อิศรางกูร ณ อยุธยา, RTGS: Chirayu Itsarangkun Na Ayutthaya, Thai pronunciation: [t͡ɕìʔraːjúʔ ʔìtsàʔraːŋkuːn náʔ ʔàʔjúttʰáʔjaː]; born 12 November 1942) is a Thai economist and court official. He has been the Director-General of the Crown Property Bureau and Grand Chamberlain of the Bureau of the Royal Household since 1987 and become Lord Chamberlain of the Royal Household in the end of 2016. Chirayu is an avowed proponent of the "sufficiency economy" philosophy that is promoted by King Bhumibol Adulyadej.