Marga is a term in Batak societies referring to a clan name and Marga is similar with family surname. The term is derived either from the Sanskrit varga, meaning company, party, or group, or, more likely, from the Sanskrit marga, meaning 'road, way or path', referring to a people of 'one origin'.
Batak marga are patrilineal. Marriage in the same Marga is strictly forbidden by tribal law (adat) even between people only distantly related; but it is allowed and often even arranged between cousins of the maternal line (boru). After marriage, Batak women do not change their family (marga) name, but add "boru" to their birth name. Since Batak marga are patrilineal, the children will inherit the marga from their father.
In Batak Toba mythology, Marga are traced to the common ancestor "Si Raja Batak" (The King of the Batak). In Karo mythology, the five Marga (Merga Silima) are defined in terms of matrimonial bonds, with no importance placed on a common ancestor myth. Simalungun have four basic marga, each seen as equal, and likewise with no common ancestor myth. 
Examples of Marga
- Nasution: Abdul Haris Nasution (Indonesian Army general), Darmin Nasution (economist)
- Batubara: Adam Malik Batubara (3rd Vice President of Indonesia), Cosmas Batubara (former minister during Suharto era)
- Nainggolan: Radja Nainggolan (footballer)
- Hutapea: Hotman Paris Hutapea ( Lawyer )
- Purba: Ir. Petrus Purba ( Palm Oil Plantation Soil Guru )