Tetrad may refer to:
- Tetrad (chromosomal pairing), Bivalents or Tetrad of homologous chromosomes consisting of four synapsed chromatids that become visible during the Pachytene stage of meiotic prophase
- Tetrad (pollen formation), group of four haploid and immature pollen grains in tetrahedral fashion produced by meiotic microsporogenesis
- Tetrad (genetics), the four spores of a yeast
- Tetrad (general relativity), a mathematical frame of reference in general relativity
- Tetractys (or Tetrad), (Greek philosophy)
- Tetrad (index notation), a concept in differential geometry
- Tetrad (music), a set of four notes
- Tetrad (unit of area), an area 2km x 2km square
- Tetromino, a shape composed of four squares
- Tetrad of media effects, a pedagogical tool