The Ancient and Auspicious Order of the Nine Gems (Thai: เครื่องราชอิสริยาภรณ์อันเป็นโบราณมงคลนพรัตนราชวราภรณ์; RTGS: Khrueang Ratcha-itsariyaphon An Pen Borannamongkhon Noppharat Ratchawaraphon) was established in 1861 by King Mongkut (Rama IV) of the Kingdom of Siam (now Thailand).

The order is bestowed upon the members of the Thai royal family and distinguished high-ranking officials who have given service to the kingdom and who are active Buddhist laypeople.

The nine gems are the Thai form of the original Hindu royal amulet known as the navaratna and in its original form consisted of a ring of gold bearing the nine gems awarded to a Thai general after he won an important military victory and is also part of the royal insignia given the Thai king at his coronation.

The nine precious stones of the royal amulet constitute an integral part of both the badge and the star of the order.

The nine gems and the corresponding benefits that they bestow on their bearers are: The decoration consists of a single class (knight).