In mathematics, an exact couple, due to William S. Massey (1952), is a general source of spectral sequences. It is common especially in algebraic topology; for example, Serre spectral sequence can be constructed by first constructing an exact couple.
For the definition of an exact couple and the construction of a spectral sequence from it (which is immediate), see Spectral sequence § Spectral sequence of an exact couple. For a basic example, see Bockstein spectral sequence. The present article covers additional materials.