Si Kefa (Chinese: 思可法; pinyin: Sī Kěfǎ) was the Dai ruler of the Kingdom of Mong Mao from 1340 to 1371. Different transliterations of his name in the local Tai language include "Hso Kip Hpa" or "Sa Khaan Pha".
Si Kefa engaged in repeated raiding on neighboring chieftainships and in 1348-49 the Yuan court sent an expedition under Marshall Dashibadu to put an end to it. The expedition failed to subdue him, but Si did send his son Mansa to the Yuan court to offer allegiance. The Baiyi Zhuan reports that while Mansa "accepted the Court's calendar and offered tribute, his clothing, paraphernalia and system remained like those of a king." Both the Mong Mao and Hsenwi chronicles provide lists of the far-flung domains he is said to have controlled reaching to the border of the Kingdom of Dali in the north, Xishuangbanna to the south, Burma to the east, and Yongchang to the west.
Si has a privileged position in Mong Mao chronicle history as defining "an age when the Tay [Tai] lived in an expansive independent kingdom ruled by their own kings and use it as a point of departure for their accounts of post-fifteenth century history"