Rajakaruna (; ) is a Sinhalese surname. Notable people with the surname include:
Denuwan Rajakaruna (born 1990), Sri Lankan cricketer Harshana Rajakaruna (born 1980), Sri Lankan politician Sarathchandra Rajakaruna (1940 – 2011), Sri Lankan politician Sobitha Rajakaruna, Sri Lankan puisne justice of the Supreme Court Upali Rajakaruna (born 1975), Sri Lankan wheelchair tennis player
See also Cnemaspis rajakarunai, also known as "Rajakaruna's day gecko", a species of geckos found in Sri Lanka