Doric, Ionic, and Corinthian capitals are the primary type of classical Greek columns. A capital is the crowning, decorative part of a column that transitions from the columnade to the supporting masonry. As relics of the Classical world, they can help to date buildings and understand architecture.

Doric capitals, like those of all Greek columns, are comprised of a rectangular slab above a circular one. Made famous by the Greek Parthenon, Doric columns stand plain and smooth. Their abacus, the rectangular crown, is often a single piece of marble. The echinus, the circular slab, is sometimes carved with figures of Gods. Created as early as 600 BCE, these columns are sturdy and elegant.

Contemporaneous with Doric, Ionic columns became a slightly more decorative alternative. Their most distinctive feature is their scrolls, called volutes. That shape resembles a piece of paper rolled up from both ends resting on the top of the columnade, with an oculus, or eye, at the spiral's center. The volute was nspired by the curling ringlets of the goddess Diana. The ornamental molding, the cymation, shows a series of beaded motifs called egg-and-tongue or egg-and-dart between the volutes. An example of these columns can be seen on the Erechtheum temple in Greece.

Corinthian capitals are the most elaborate style. They borrow volutes from Ionic, accenting the four corners of the abacus. On the strips of decorative molding, called modillions, spring acanthus leaves, palmettes, and even rosettes. Romans, more than Greeks, utilized this column starting in the mid-4th century CE. A sculptor was supposedly inspired by something he saw at a tomb. A young maiden died during winter, and her nurse placed a basket of her belongings by her grave, covered by a tile to protect them. She happened to put it on top of a dormant acanthus vine. Come spring, the vine pushed through, surrounding the basket with leaves, and curling the sides of the tile.

During Greek architectural revivals, two other related column capitals decorated buildings: Tuscan and Composite. Like the Doric, the Tuscan is very plain. Composite capitals combine Ionic and Corinthian styles. There are a few non-Greek capitals associated with other architectural movements. A medieval column used historiated capitals to depict stories or emphasize symbolic meaning through carved animals, birds, and people in the 11th and 12th centuries. During the first Gothic period, a crocket capital, based on the Corinthian, used tiers of clusters of foliage.