Sumali (Malay: Sumaliwan, Tamil: Chumali, Thai:ท้าวสหมลิวัน) is the maternal grandfather of Ravana, the principal antagonist of the Ramayana. He was a Rakshasa King.
He, his elder brother Malyavan and younger brother Mali were the sons of the RakshasaSukesha. Sumali along with his two brothers made a tapasya to Brahma and asked that their brotherly love would be unbreakable and no one would be able to defeat them. Consequently, they conquered every Aditya and Daitya. With these powers they asked Vishvakarma to make a city for them. Thus they received Lanka where they lived in luxury. Later they were defeated by the gods and Mali was killed by Vishnu.
Sumali's wife was Ketumati with which he had ten sons - Prahastra, Akampana, Vikata, Kalikamuka, Dumraksha, Dandha, Suparshva, Sanhadi, Barkarna and four daughters - Raka, Pushpotyata, Kaikasi, and Kumbhinasi. Thataka, a Yaksha princess, is also named as his wife. She bore Sumali two sons, Subahu and Maricha, and a daughter, Kaikesi. Kaikesi was married to sage Vishrava and their son Ravana reconquered Lanka.Other sons of Kaikesi were-Kumbhakarna and Vibhishana. She has a daughter named Shurpanakha.