| Native Name: | ﻛﺴﻠطﺎﻧﻦ سردڠ |
| Conventional Long Name: | Sultanate of Serdang |
| Religion: | Islam |
| Year Start: | 1723 |
| Year End: | 1946 |
| Event End: | East Sumatra revolution |
| Image Map Caption: | The territory of the Sultanate of Serdang in 1930 (orange) |
| Capital: | Perbaungan |
| Common Languages: | Malay |
| Government Type: | Monarchy Sultanate |
| Title Leader: | Sultan |
| Leader1: | Tuanku Umar Johan Pahlawan Alam Shah |
| Year Leader1: | 1723-1782 |
| Leader2: | Sultan Sulaiman Syariful Alam Shah |
| Year Leader2: | 1879-1946 |
| Leader3: | Sultan Achmad Thalaa Shariful Alam Shah |
| Year Leader3: | 2011-Now |
| Today: | Indonesia |
The Sultanate of Serdang (Malay: ﻛﺴﻠطﺎﻧﻦ سردڠ) was an early modern Malay-Indonesian monarchy, Serdang was founded in 1723 and joined the Republic of Indonesia in 1946. The Sultanate separated from the Sultanate of Deli after a dispute over the royal throne in 1720. Like other kingdoms on the east coast of Sumatra, Serdang prospered due to the opening of tobacco, rubber and oil palm plantations.
According to history, an Laksamana from Sultan Iskandar Muda Aceh named Sri Paduka Gocah Pahlawan, have a title Laksamana Khoja Bintan, married to the younger brother of Raja Urung (state) Sunggal, a Karo Tribal area that already converted to Islam. Then, by the 4 Kings of the Urung Karo tribe who were already Muslim, this Laksamana was appointed king in Deli in 1630. With that event, the Kingdom of Deli was officially established, and the Laksamana became the first Deli King. In the coronation process of the Deli King, King Urung Sunggal was in charge as Ulun Jandi, namely to say obedience from the Big Men and people to the king. Then, the Datuk Empat Institution was formed, and Raja Urung Sunggal was a member of the Datuk Empat Institution.
In its development, in 1723 there was chaos when Tuanku Panglima Paderap, the 3rd Raja Deli died. This crisis happened because the eldest son of the King who was supposed to replace him had a defect in his eyes, so he could not become king. Son number 2, Tuanku Pasutan who was very ambitious to become king then took over the throne and expelled his younger brother, Tuanku Umar with his mother, Permaisuri Tuanku Puan Sampali, to Serdang region.
According to Malay custom, Tuanku Umar was supposed to replace his father as the Deli King, because he was the son of garaha (permaisuri), while Tuanku Pasutan was only a concubine. However, because he was still a minor, Tuanku Umar was finally eliminated from the Deli. To prevent civil war from happening, the 2 Great Men of Deli, namely Raja Urung Sunggal and Raja Urung Senembal, together with an East Urung Batak King in the upstream Serdang region (Tanjong Merawa), and an official from Aceh (Lumu Kejeruan), then rationing Tuanku Umar as the first Serdang King in 1723. Since then, the Serdang Kingdom has been established as a fraction of the Deli Kingdom.