To ensure the systematic, coherent and rational description of objects in and across collections, metadata standards for subject indexing have therefore been established. These metadata standards have evolved over time to accommodate changing needs, growing and diversifying collections, and emerging digital affordances. Yet, for numerous reasons, subject metadata are neither fully nor rigorously implemented in many of today’s catalogues – whether in the backend indices or the front-end end-user interfaces – to the detriment of users. Online public library catalogues, discovery services, journal article databases, university repositories and museum catalogues all demonstrate shortcomings in how subject metadata are integrated, consolidated and leveraged (Golub 2016; Golub 2018; Golub et al. 2020; Golub, Ziolkowski and Zlodi 2022). Properly incorporated, subject metadata could greatly improve the discovery of objects within collections and (because collections are increasingly connected online) the reconciliation of descriptive information across different collections for better cross-database searching. On the other hand, digital technologies could make standardised subject access finally realise the potential always envisioned for it. To make this argument, we explore subject access and associated metadata standards in library and museum cataloguing.