Yodtong Siriwalak (28 August 1937 – 8 February 2013) most commonly known by his Muay Thai ring name Yodtong Senanan or Kru Tui was a Muay Thai fighter, trainer, and owner of the Sityodtong Muay Thai Camp in Chonburi, Thailand. He has produced 57 Muay Thai Champions, the most number in the history of Muay Thai in Thailand. His most famous Muay Thai World Champions include Samart Payakaroon, Kongtoranee Payakaroon, Nuengpichit Sityodtong, Detpitak Sityodtong, Chartchai Sityodtong, Yoddecha Sityodtong, Daotong Sityodtong, and others. Additionally, top Muay Thai, K-1, and UFC professional fighters from around the world such as Rob Kaman, Ramon Dekkers, Ernesto Hoost, Peter Aerts, Musashi, Kenny Florian, Antonio Braga Neto, and many others have made pilgrimage to the Sityodtong Gym in Pattaya to train and sharpen their skills. His top trainers include Saknarong Sityodtong, Daorung Sityodtong, Chatri Sityodtong, Yodsanan Sityodtong, Kongtoranee Sityodtong and others.

Yodtong started training in Muay Thai when he was fourteen years old under Kru Sithidet Samanachan and he had his first fight shortly after his fifteenth birthday. His first ring name was Erawan Detprasit Banpra (after his camp, Detrprasit, and his stadium, Banpra). At the age of seventeen, Erawan moved to the Senanan camp to train under Kru Suwan Senanan, and adopted the surname of his teacher as his ring name. There he first started instructing other fighters in Muay Thai. He continued to fight professionally until the age of twenty-one, after which he went into semi-retirement, fighting only if the money was right. Yodtong had a total of forty nine fights.

Yodtong founded his own camp in 1959 at Mabtapud municipality, Rayong province. He stayed in Mabtapud for approximately 15 years, before moving it to Banglamung district of Chonburi, where it remained. In 1971, Daothong Sityodtong became the first champion produced by the gym, winning the Lumpini Stadium Championship. In 1972, Yodtong’s fighters engaged in a memorable feud with Japanese kickboxers led by Osamu Noguchi.

In 1 November 2005, Yodtong won the 1st prize in the lottery, worth 56 million baht. He saved approximately 10 million baht for himself and donated the rest to various social causes. This made him very popular in Banglamung district.

Kru Yodtong appointed one of his students, Chatri Sityodtong, to be conservator of Muay Thai in Asia. Mark Dellagrotte of UFC fame is a conservator of Muay Thai in the US under Kru Yodtong Senanan. There are several Sityodtong Muay Thai camps around the world.

Kru Yodtong Senanan resided in Chonburi province, Thailand until his death in 2013.