Tetrad may refer to:

• Tetrad (chromosomal formation), a chromosomal formation in meiosis
• Tetrad (general relativity), a mathematical frame of reference in general relativity
• Tetrad (genetics), the four spores of a yeast
• Tetrad (Greek philosophy), the first number formed by the addition and multiplication of equals
• 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