The 2nd Mass Timber Research Needs Assessment was held on November 13–14, 2018, at the USDA Forest Service, Forest Products Laboratory (FPL). The workshop was co-sponsored by FPL, WoodWorks, and the U.S. Endowment for Forestry and Communities. The purpose of the workshop was to gather a diverse group of people with expertise in mass timber, in particular cross-laminated timber, to discuss and prioritize research needed to move the mass timber industry forward in North America. The workshop was attended by more than 100 design professionals, researchers, manufacturers, industry leaders, and government employees. The meeting resulted in a list of 117 research needs. Following the meeting, the list of research needs was prioritized through an online survey. This report presents the prioritized research needs of the mass timber industry in North America. Also included in the appendixes are the formal minutes of the workshop, a list of participants, and the original scribe notes.