Low-carbon prefabricated modular construction systems, using prefabricated engineered solid wood panel construction systems, such as load-bearing glue-lam columns or cross-laminated timber panels, and “design for disassembly” principles can offer significant opportunities for greenhouse-gas emission reduction and construction waste avoidance, among other benefits. As mass timber construction has evolved from a niche product to a mainstream system, there is an urgent need for focused research activities to support the industry and avoid duplication of work being done internationally. To identify and prioritise the future of mass timber research agenda, this chapter pursues responses to the following question: What is the current state of knowledge and where are the remaining research needs in mass timber construction? For example, newcomers to mass timber often believe it is imperative to mostly research fire performance, fire resistance, or sound transmission, when these areas have been extensively explored and are widely seen as resolved. The focus has shifted, towards answering new research questions, including explorations of carbon storage, whole-life cycle analysis, and durability. There is already a growing research activity in mass timber, involving several research centres worldwide. Thus, defining trends and knowledge gaps will help avoid replicating research. A more nuanced discussion on knowledge gaps and industry research needs is also timely, to truly capture and disseminate information on the full potential of engineered-mass timber systems as an innovative construction method, which helps reducing the use of carbon-intensive conventional building materials. To answer the above-mentioned research questions, the author has consulted experts and seven key research areas have been identified and presented.Body of knowledgeBody of knowledge