Gate Mudaliyar Arunachalam Ponnambalam, JP, UM (1814 – 4 September 1887) was a Ceylonese colonial-era government functionary, businessman and philanthropist.

[1][2] Through his paternal line Ponnambalam is believed to be a descendant of Mana Mudaliyar of Thondai Nadu, one of the pioneer settlers of Jaffna peninsula in the late 15th century.

[3] In 1830, aged 16, Ponnambalam was sent to Colombo to live with Gate Mudaliyar A. Coomaraswamy and his wife Visalachchi.

[4] Ponnambalam married Sellachi Ammai, daughter of Gate Mudaliyar A. Coomaraswamy, on 24 January 1844.

[6] A few months after the death of Gate Mudaliyar A. Coomaraswamy, Ponnambalam was appointed landing waiter and searcher at the Customs Department but the fees he had to pay to various public officials meant that he earned little from the job.

[13][12] Ponnambalam started losing interest in his work in 1851, and after his wife died in September 1854, he resigned from his position as cashier at the Colombo Kachcheri on 30 November 1854.