This special issue asks how product lifetime extension in a circular economy can best be understood and managed. Product lifetime extension through design for durability, reuse, repair, refurbishment and remanufacture, and the associated circular business models, are regarded as an important way forward to achieving a circular economy. As a research field, it has however not received much attention. The collection of 24 papers was partly drawn from the PLATE 2017 conference (Product Lifetimes and the Environment), November 2017 in Delft, the Netherlands. This special issue introductory article provides an overview of the content of the articles, divided into three topics: product design in a circular economy, circular business models, and environmental & economic impact assessment. One of the overall findings is that there is a lack of empirical validation and critical evaluation of many of the widely-held assumptions about design and business model innovation for product lifetime extension. More empirical research is needed in order to build a repertoire of validated approaches, cases, tools and methods, taking into account rebound effects.