This introduction to a special issue about the United Nations’ observances (days, weeks, years, decades) explores how scholarly engagement with UN observances may provide fresh perspectives on diplomatic history. The introduction discusses the origins of these observances and the limited historiographical attention they have received. It argues that observances need to be conceptualized and historicized as “diplomatic scripts.” This approach helps to understand how the UN has functioned as a diplomatic platform and how the UN, especially since the 1970s, has been used by a broad range of diplomats in different locations and with different agendas. It highlights the diversity of diplomatic activity beyond the state-to-state model and uncovers actors and processes that have stood in the shadow of well-known diplomatic events and developments. The last part of the introduction provides a short overview of this special issue.