In abstract algebra, commutative algebra is the field of study of commutative rings, their ideals, modules and algebras. It is foundational both for algebraic geometry and for algebraic number theory. The most prominent example for commutative rings are polynomial rings.

The subject's real founder, in the days when it was called ideal theory, should be considered to be David Hilbert. He seems to have thought of it (around 1900) as an alternate approach that could replace the then-fashionable complex function theory. In line with his thinking, computational aspects were secondary to the structural. The additional module concept, present in some form in Kronecker's work, is technically an improvement on working always directly on the special case of ideals. Its adoption is attributed to Emmy Noether's influence.

Given the scheme concept, commutative algebra is reasonably thought of as either the local theory or the affine theory of algebraic geometry.

The general study of rings that are not required to be commutative is known as noncommutative algebra; it is pursued in ring theory, representation theory and in other areas such as Banach algebra theory.

For links, see list of commutative algebra topics.