Kostas Giannidis (born Giannis Konstantinidis) (1903-1984) was a popular Greek composer, pianist and conductor of the early and middle 20th century.
He was born in Smyrna in 1903. He came in Greece after the destruction of Smyrna and continued his studies in Berlin (1923-1931). He returned in Athens and worked as a conductor and composer at the musical theatre composing many operettas, musical comedies and revues. He composed also music for seven Greek movies (The Germans Strike Again, Ο methistakas/The Drunkard and others).
He wrote also symphonic, chamber music, compositions for piano and many popular songs. Among his compositions were also some rebetiko pieces.