Navaandorjiin Jadambaa (Mongolian: Наваандоржийн Жадамбаа) was the first republican Head of State of Mongolia. He became Chairman of the State Great Hural in November 1924 following the death of the Bogd Khan. Only a day later he was replaced by Peljidiin Genden.
Usually a regency would follow the death of the Bogd Khan until his reincarnation had reached his majority; however, in this case the search for the reincarnation of the Bogd Khan was banned (his reincarnation was discovered in Tibet in 1936) and the country has maintained a republican constitution ever since.