There are around 31 species of Old World warblers. Most occur in Europe, Asia, and Africa.

They are small birds, usually measuring 3.5–10 inches (8.9–25.4 cm) in length. They have slender, pointed bills, rounded wings, short tails, and short-to-medium legs.

Their feathers are usually brown, gray, or olive green, sometimes with streaks or bars. Some species have brighter colors or more noticeable markings.

They live in a variety of habitats, including forests, shrublands, grasslands, and wetlands. Most eat insects, although some also eat fruit and seeds.

Many Old World warblers are known for their songs, which can be complex and melodious. Their songs help them attract mates and communicate with other birds.