Loi Krathong (or Loy Kratong, Thai ลอยกระทง) is a festival celebrated annually throughout Thailand on the full moon night of the 12th lunar month, which usually falls on some day in November. This year, Loi Krathong Day is November 24, 2007. "Loi" means "to float". "Krathong" is a raft about a handspan in diameter traditionally made from a section of banana tree trunk (although modern-day versions often use styrofoam), decorated with elaborately-folded banana leaves, flowers, candles, incense sticks etc. The floating of a Krathong – a banana-leaf cup – is to float away ill fortune, to create good luck, and to express apologies to the Goddess of Water, Phra Mae Khongkha.

The beauty contests that accompany the festival are known as "Noppamas Queen Contests". According to legend, Noppamas was a consort of the Sukhothai King Loethai (14th century) and she was the first person to float a decorated krathong.