In 2018, the US Army Corps of Engineers and Washington and Waukesha Counties in Wisconsin hosted a workshop on the invasive macroalga starry stonewort (Nitellopsis obtusa). Leading water resource managers (agencies and commercial applicators), researchers, regulators, and other interested parties discussed issues surrounding starry stonewort invasions in the Great Lakes Region (GLR). Technical sessions presented information on current research, invasion monitoring, early detection, rapid-response efforts, and operational management activities. Research summaries included invasion in Lake Ontario, prediction of invasion risk in Minnesota and Wisconsin using water chemistry data, and bulbil efficacy and distribution modeling in New England. In addition, the workshop offered summaries of attempted chemical and mechanical control tactics. Following presentations on previous studies, workshop participants identified research and management priorities. Critical research gaps identified from this workshop include (a) better understanding of the biology, invasion ecology, and management of starry stonewort; a greater understanding of distribution and movement, especially in the Great Lakes basin; enhanced population monitoring, applied research, and management strategies; and increased technical cooperation across government, academia, industry, and nonprofit organizations. Conclusions from this meeting will help prioritize future efforts focused on the adaptive management of starry stonewort in the United States and Canada. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.