Somdet Chao Phraya Borom Maha Prayurawongse (Thai: สมเด็จเจ้าพระยาบรมมหาประยูรวงศ์; RTGS: Somdet Chao Phraya Borom Maha Prayurawong) or Tish Bunnag (Thai: ดิศ บุนนาค; RTGS: Dit Bunnak; 1788–1855) was a prominent political figure of Siam during the mid-19th century as a regent for Mongkut kingdom-wide. He led Siamese fleets in the Siamese-Vietnamese Wars and became a Somdet Chao Phraya — the highest title the nobility could attain, with honor equal to that of royalty.

Tish Bunnag was born in 1788 to Bunnag and Lady Nuan (who was Queen Amarindra's sister). His father, Bunnag, or Chao Phraya Akkaramahasaena, was the Samuha Kalahom and Buddha Yodfa Chulaloke's trusted general.

Tish entered the palace as one of the royal pages - the traditional way to Siamese bureaucracy. Dis swiftly rose in ranks and became the Minister of Kromma Tha and emerged as a powerful noble under the government of Buddha Loetla Nabhalai.

During the Siamese-Vietnamese Wars, in 1833 Dis led the Siamese fleet to imposed the naval blockade upon Saigon but without achieving fruitful results. King Nangklao then offered him the title of Chao Phraya Akka Mahasena but he turned it down saying that the Chao Phraya Akka Mahasena died early. He then became the Samuha Kalahom.

As Tish had played a great role in the ascension of Mongkut, he was bestowed the title of Somdet Chao Phraya Borom Maha Prayurawongse and became Mongkut's regent kingdom-wide along with his brother Tat Bunnag who became Somdet Chao Phraya Borom Maha Pichaiyat and Mongkut's regent in Bangkok. Prayurawongse was granted the right to use the Solar-charioteer Seal (Thai: ตราสุริยมณฑลเทพบุตรชักรถ) Prayurawongse was noted for his role in the negotiation of the Bowring Treaty. To distinguish him from his brother, Prayurawongse was also called the Greater Somdet Chao Phraya (Thai: สมเด็จเจ้าพระยาองค์ใหญ่) while his brother was called the Lesser Somdet Chao Phraya (Thai: สมเด็จเจ้าพระยาองค์น้อย).

His notable sons included;

  • Chuang Bunnag; later Somdet Chao Phraya Borom Maha Sri Suriyawongse - regent for Chulalongkorn
  • Kam Bunnag; later Chao Phraya Thipakornwongse - the Minister of Kromma Tha
  • Tuam Bunnag; later Chao Phraya Panuwongse - the Minister of Kromma Tha for Chulalongkorn and the first Minister of Foreign Affairs of Siam
  • Thet Bunnag; later Chao Phraya Suraphan Phisut
  • Porn Bunnag; later Chao Phraya Bhasakornwongse

Prayurawongse died in 1855. His son, Kam Bunnag, succeed the Ministry of Kromma Tha.