Yotfa (Thai: ยอดฟ้า) or Kaeofa (Thai: แก้วฟ้า) was the 14th Ayutthayan king from the Suphannaphum Dynasty.
Yotfa was a son of King Chairachathirat (พระไชยราชาธิราช) and his consort Lady Si Suda Chan (ท้าวศรีสุดาจันทร์). He reigned from 1546 until his death by murder.
Thai chronicles recorded that in 1548, Lady Si Suda Chan eventually summoned all government officers and said to the meeting that Yotfa was too young to rule the kingdom and that "I will place Khun Worawongsathirat in charge of public administration until my son is mature enough". As no one objected, Lady Si Suda Chan ordered the Ministry of Palace Affairs to hold a royal chariot procession to bring Khun Worawongsathirat into the palace and hold his coronation.
After becoming king, Khun Worawongsathirat ordered Yotfa to be executed at Khok Phraya Temple (วัดโคกพระยา) but spared his brother, Prince Sisin. The Astrological Annals recorded that the execution was held on Sunday, the fifth day of the waxing moon in the eighth month of the 910th year of the Minor Era, corresponding to 10 June 1548. Yotfa had been on the throne for about two years and was around thirteen years of age when he was executed.
Lady Si Suda Chan, as well as her paramour and newborn daughter, were later killed in a countercoup staged by senior government officers, led by Khun Phirenthrathep (ขุนพิเรนทรเทพ). The coup makers then offered the throne to Prince Thianracha.