"Overo" is the name of a coloration pattern in horses. Any breed which can be pinto can have the overo pattern. Overo is a recessive gene. Overos commonly have fully blue or partially blue eyes.

In "frame overo", the horse appears to be any solid colour (bay, black, chestnut, etc) with white irregular patches added. The white rarely crosses the back, the lower legs are normally dark but can have one or two white socks, and the tail is one color. Some frame overos can have a genetic mutation, and when two horses positive for the mutation are bred together, there is a chance that they will have a foal positive for lethal white syndrome. The foals will completely white with brown eyes and pink skin (however, these horses should not be confused with cremellos, perlinos, smoky creams, or sabinos, as these will often be completely white with pink skin). The foal's digestive system will be undeveloped. All lethal white foals will be euthanized.

A "splash overo" pattern appears like a solid coloured horse who has been dipped in white paint, and the colour splashed up from the bottom. Splash horses are more prone to being deaf than other horses.

"Sabino overos" generally have four jagged white stockings, a blaze (crooked blazes are common with sabino), and small white patches on the underbelly. True sabinos will never have blue eyes.