Marissa Mastors

Marissa Mastors joined GMRI in 2025 as the Executive Assistant to the COO. She holds a B.A. in anthropology from Skidmore College and an M.A. in Leadership for Sustainability Education from Portland State University.

Marissa brings a wealth of experience in nonprofit development and management. She has supported environmental- and community-centered organizations, including the Central Park Conservancy, Just Communities (formerly EcoDistricts), and Wolfe’s Neck Center for Agriculture & the Environment. Before joining GMRI, she served as the Executive Manager for At The Well, an international nonprofit at the intersection of Judaism and women’s wellness. She is a certified Master Gardener and has earned two Permaculture Design Certificates.

Marissa finds joy in getting her hands in the dirt, trail running, baking challah, and embracing communal living with college friends in the North Yarmouth woods. She loves spending time outdoors with her husband and young daughter.