The sand martin, also known as the bank swallow, collared sand martin, or common sand martin, is a migratory passerine bird in the swallow family. It has a wide range in summer, embracing practically the whole of Europe and the Mediterranean countries and across the Palearctic to the Pacific Ocean. It is a Holarctic species also found in North America. It winters in eastern and southern Africa, South America, and the Indian Subcontinent.

The swallows, martins, and saw-wings, or Hirundinidae are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica. Highly adapted to aerial feeding, they have a distinctive appearance. The term "swallow" is used as the common name for Hirundo rustica in the UK and Ireland. Around 90 species of Hirundinidae are known, divided into 19 genera, with the greatest diversity found in Africa, which is also thought to be where they evolved as hole-nesters. They also occur on a number of oceanic islands. A number of European and North American species are long-distance migrants; by contrast, the West and South African swallows are nonmigratory.