Rosanna "Rosie" ʻAnolani Alegado (born 1978) is a Kanaka ʻōiwi/Native Hawaiian Associate Professor of Oceanography at the Daniel K. Inouye Center for Microbial Oceanography as well as director of the Hawai‘i Sea Grant’s Ulana 'Ike Center of Excellence at the University of Hawaii at Manoa. Alegado studies the evolution of host–microbe interactions and the microbial ecology of coastal estuarine systems.