There are seven Old Testament prophets on the Sistine Chapel ceiling.
Michelangelo included four major prophets—Isaiah, Jeremiah, Ezekiel, and Daniel—and three of the Twelve Minor Prophets: Joel, Zechariah, and Jonah. These figures occupy large triangular or curved spandrels around the ceiling’s central Genesis scenes.
The prophetic figures form part of a theological program commissioned by Pope Julius II and painted between 1508 and 1512. They represent anticipation of the coming Messiah and connect the Old Testament imagery on the ceiling with Christian ideas about salvation.
The number can be confused because the ceiling contains twelve prophetic figures in total: seven male prophets from Israel and five Sibyls. The Sibyls were female prophetic figures associated with the classical Greek and Roman world, not Old Testament prophets. The ceiling also includes nine central scenes from Genesis, so answers such as nine or twelve count different groups of imagery rather than the Old Testament prophets themselves.