Thommayanti is the pen name of Thailand National Artist Khun Ying Wimon Chiamcharoen, who was born as Wimon Siriphaibun. She is a Thai novelist and has been a legislator several times in her career.

Among her works there is the historical fantasy romance novel, Thawiphop, about a woman who time travels from the 20th century to Rama V-era Siam. The story was first adapted as a film by Cherd Songsri in 1990, and has since been adapted as a stage play, a musical, a television series, and a 2004 film (Siam Renaissance).

Another of Thommayanti's works is Khu Kam, about the romance of a Thai woman and a Japanese soldier during World War II in Thailand. It has been adapted into two films, Sunset at Chaophraya (in 1996 and 2013), a stage musical, and a television series. Among her famous works are the romantic love story Dang Duang Haruethai and the socially conscious and inspiring rag-to-riches tales Sapan Dao.

Apart from her writing ability, she is a noted orator. On several occasions, Wimon gave public speeches in favour of the military. During the coup d'état in the 6 October 1976 Massacre, Wimon played important role in the "housewife society", a group of wives of military generals. She also made public speeches against the students who agitated for democratic reform, saying that the students were destroying Thailand's good relationship with the United States. In that event, students were mass murdered and Wimon was appointed by the junta that took control of the country as a legislator and member of the National Reform Council. Later in 1979, Wimon was elected as a senator.

In 1986, the Supreme Court of Justice found Wimon, while serving as a senator, guilty of having committed adultery with Group Captain Akhom Atthawetworawut, an officer who was also a senator, after Police Major Siwit Chiamcharoen, her husband, filed divorce proceedings and a claim for compensation. After the Supreme Court's judgment, the Senate resolved to dismiss Wimon from senatorial office.

In spite of the Supreme Court's conviction, King Bhumibol Adulyadej awarded Wimon the royal title Khun Ying in 2005.

In 2012, the Ministry of Culture of the Kingdom of Thailand, through the Department of Cultural Promotion, honoured Khun Ying Wimon with the highest honour bestowed upon Thai artist by naming her "National Artist" (Literature).