The importance of knowledge and innovation in modern economies justifies the in-creasing interest that scholars are taking in studying knowledge-intensive business services (KIBS). The objective of this paper is to track the evolution of the key dimen-sions on which scholars have based their analyses through a literature review. More specifically, three main issues are addressed: (1) how KIBS are defined in the litera-ture; (2) how KIBS have been investigated empirically by researchers; and (3) how the analysis of KIBS has evolved over time. As a major assumption, the analysis catego-rises the research topic into three key conceptual dimensions: (i) knowledge; (ii) inno-vation and (iii) spatial proximity. The major hypothesis is that the way KIBS are seen, studied and perceived by the research community resolutely changed over time and that this evolution can be tracked by observing modifications in the key dimensions associated with the analysis of KIBS.