In Tanzania, local radio stations—including station managers, journalists, and DJs—act as trusted messengers and influencers, including on health information and behavior. Early in the Covid-19 pandemic, media restrictions limited the ability of radio to respond to Covid-19. But local radio stations generally want to serve their communities with accurate and relevant public health information. Now, with restrictions loosened, an interdisciplinary team will partner with local radio stations over two years to assess the effects of a nationwide campaign, Afya Yako (“Your Health” in Swahili). Researchers will randomly assign 30 hyper-local radio stations (a mix of for-profit, community, and donor-driven radio) to air this campaign, with another 30 stations acting as a control group. A subset of villages within the campaign’s broadcast radius will also receive an in-person mobilization campaign, and a subset of citizens within the broadcast radius will be invited to participate in Afya Yako WhatsApp groups. Over two years, researchers and radio stations will assess the impact of the program on Covid-19 vaccination knowledge, attitudes, and uptake, as well as trust in and use of essential health services. Beyond the campaign’s immediate impact, researchers hope that the project will equip interested parties at local radio stations with the knowledge and skills to recognize and dispel misinformation as it emerges.