This is a timeline of category theory and related mathematics. Its scope ("related mathematics") is taken as: * Categories of abstract algebraic structures including representation theory and universal algebra; * Homological algebra; * Homotopical algebra; * Topology using categories, including algebraic topology, categorical topology, quantum topology, low-dimensional topology; * Categorical logic and set theory in the categorical context such as ; * Foundations of mathematics building on categories, for instance topos theory; * , including algebraic geometry, , etc. * Quantization related to category theory, in particular categorical quantization; * relevant for mathematics.