Undang

The Undang Yang Empat (Negeri Sembilan Malay: Undang Nan Ompek; Jawi: أوندڠ يڠ امڤت) are the ruling chiefs or territorial chiefs who play an important role in the election of a new Yang di-Pertuan Besar of Negeri Sembilan, Malaysia. The name is believed to be derived from the Malay word undang-undang meaning "law".

The Minangkabau who settled at Negeri Sembilan, in present-day Malaysia at the end of the 17th century ruled by a "penghulu" or headman who was chosen from the noble families of Sakai and Jakun belonging to the Biduanda clan. These "penghulus", notably that of Sungai Ujong, Jelebu, Johol and Rembau became powerful enough to exalt themselves above the other "penghulus". These penghulus later acknowledged by the sultan of the old Johor Empire as a sovereign in their own territory. By the early part of the 18th century, the leaders of these four territories started using the title "Undang" to distinguish themselves from other penghulu luak.

Malaysia's modern day constitution confirms the status of the Undang under Article 71, 160, 181 and the Eight Schedule of Federal Constitution as Malay Ruler within the Federation. Undangs are still chosen from amongst certain noble families in the state, the succession being both matrilineal and elective following the Adat Purbakala.