Maaja Ranniku (1 March 1941 – 24 October 2004) was an Estonian chess player (represented the Soviet Union until 1991).
She was twice the winner of the Women's Soviet Championship: in 1963 (after beating at tiebreak Tatiana Zatulovskaya 4-2) and 1967.
Maaja Ranniku participated in many Estonian Championships, winning the women's title 10 times (1961, 1963, 1967, 1973, 1981, 1982, 1984, 1987, 1988, and 1991).
At the 1964 women's Candidates Tournament, played in Sukhumi, she placed 6th in a field of 18 players.
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