2061: Odyssey Three is a science-fiction novel by the British writer Arthur C. Clarke, published in 1987. It is the third book in Clarke's Space Odyssey series. It returns to one of the lead characters of the previous novels, Heywood Floyd, and his adventures from the 2061 return of Halley's Comet to Jupiter's moon Europa.

Clarke had originally intended to write the third book after NASA's Galileo mission to Jupiter had returned its findings in the late 1980s. The probe had been initially scheduled for launch in 1984 but this was delayed, first to 1985 and then to 1986. It was delayed further in wake of the Space Shuttle Challenger disaster. Deciding not to wait, Clarke took inspiration for his sequel from the return of Halley's Comet. Galileo was eventually launched by Space Shuttle Atlantis on the STS-34 mission in October 1989. It arrived in Jovian orbit almost eight years after the publication of 2061: Odyssey Three.