Substantial energy savings are still available in the lighting sector through (1) further improvements in LED efficacy, (2) widespread adoption of smart lighting systems and controls, and (3) luminaires designed for circularity. To help ensure that these additional energy savings are captured, a joint effort to develop an international lighting technology roadmap is being launched by the IEEE Smart Lighting program, the IEA 4E SSLC Platform and the International Solid-State Lighting Alliance (ISA). This paper discusses the context for this work, describes the scope of this roadmap and highlights some of the major challenges that will be faced by the lighting industry as it develops the full potential for SSL in the coming decades. This paper also provides an overview of the new work planned by the IEA 4E SSLC Platform, which will, in part, help to address some of those major challenges.