Kaljo is an Estonian masculine given name and, less commonly, a surname.

People named Kaljo include:

As a given name Kaljo Ellik (1948–2017), Estonian politician Kaljo Kiisk (1925–2007), Estonian actor, film director and politician. Kaljo Põllu (1934–2010), Estonian artist. Kaljo Pork (1930-1981), Estonian botanist. Kaljo Raag (1892–1967), Estonian weightlifter, actor and singer. Kaljo Raid (1921–2005), Estonian composer, cellist and pastor.

As a surname Dimitri Kaljo (born 1928), Estonian geologist and palaeontologist Julius Kaljo (1910–1954), Estonian footballer.