Recent trends in a range of scientific fields have seen a shift towards research and methods concerning individual differences and individualisation. This article brings together various scientific disciplines—ecology, evolution, and animal behaviour; medicine and psychiatry; public health and sport/exercise science; sociology; psychology; economics and management—and conceptually integrates their research on individualisation. We clarify the concept of individualisation by distinguishing three kinds of individualisation studied in these disciplines: IndividualisationONE as creating/changing individual differences, IndividualisationTWO as individualising applications, and IndividualisationTHREE as social changes influencing autonomy, risk, and responsibilities. This also elucidates how individualisation is related to individual differences. Drawing on recent work in philosophy of biology, we analyse conceptual links between individualisation and individuality and clarify the different sorts of individuality that the disciplines study. This paper promotes interdisciplinary research concerning individualisation by establishing a common conceptual theoretical basis, while leaving room for disciplinary differences.