De Alwis is a Sinhala surname. It is a corruption of the Portuguese surname Alves which was spread across Sri Lanka during the time of Portuguese rule of the island. Notable people with the surname include:
Anandatissa de Alwis, Sri Lankan politicianGuy de Alwis (1959–2013), Sri Lankan cricketerJames De Alwis (1823–?), Sri Lankan lawyer and writerLakshman de Alwis (1940–2008), Sri Lankan sprinter and athletics coachLanka de Alwis, Sri Lankan cricketerMalathi de Alwis, Sri Lankan feministPrasantha Lal De Alwis, Sri Lankan lawyerPremakeerthi de Alwis (1947–1989), Sri Lankan broadcaster, lyricist and television personalitySusantha De Alwis (died 2008), Sri Lankan diplomatWilliam de Alwis (1842–1916), Sri Lankan artist and entomologistLt.Colonel Sarath De Alwis (1965-1996), Sri Lankan Army OfficerShavindra De Alwis (1991-), Sri Lankan Engineer, Researcher