Lakshman is a manifestation of Adi Sesha, the 1000-headed snake on which Srihari Vishnu resides in the milky ocean. But who was the mother of Lakshman in the Ramayan. Dasharatha had three wives Kousalya, Kaikeyi and Sumitra. Sumitra gave birth to twins – Lakshman and Shatrughna.
Therefore mother of Lakshman in the Ramayana is Sumitra.
Sumitra was the daughter of King of Kashi. She was the third wife of Dasharatha.