| Katay Don Sasorith | |
| Native Name: | ກະຕ່າຍ ໂດນສະໂສລິດ |
| Birth Date: | July 12, 1904 |
| Birth Place: | Vientiane, Laos |
| Death Date: | December 29, 1959 (aged 55) |
| Death Place: | Vientiane, Laos |
| Other Names: | William Rabbit |
| Party: | National Progressive Party |
| Nationality: | Laos |
Katay Don Sasorith (July 12, 1904 – December 29, 1959) was a Laotian nationalist, politician, author, and the 8th Prime Minister of Laos (October 25, 1954 – March 21, 1956).
After working as a civil servant, Katay became chief spokesman of the national resistance movement against the Japanese and then the French, during and after World War II. He held a post as Minister of Finance in the provisional government, but had to join the government in exile in Thailand. He published a newspaper under the pseudonym William Rabbit (Katay meaning rabbit).
After returning to Vientiane in 1949, he was appointed as the Minister of Finance from 1951 to 1954. Katay was elected prime minister in 1954. In that position, he managed to play on U.S. fears of the Viet Minh invading Laos to get substantial aid for his country. He was succeeded in 1956 by prince Souvanna Phouma.
Katay Don Sasorith died in Vientiane, Laos.