Because Indigenous peoples face unique challenges to their autonomy and lifeways from dominant media influences, Indigenous radio has been used to facilitate intra-community engagement among these groups. A small but long-standing literature reveals both strengths and vulnerabilities of Indigenous radio, though the rapidly changing communications landscape suggests new possibilities for these media sources. Our research was a community–academic collaboration that employed exploratory and mixed (survey, interview, and observational) methods across two Indigenous communities in the Central and Southern Amazon of Ecuador. The Indigenous radio station, La Voz de la CONFENIAE (Confederación de las Nacionalidades Indígenas de la Amazonía Ecuatoriana), sought to perform an impact assessment that would measure both the character and extent of the impact of radio programming with sensitivity to the priorities of listeners as to the purpose, function, and appropriate impact metrics for an Indigenous radio station. A total of 92 surveys and 30 interviews across two communities were conducted in July and August of 2022. Our findings reveal (a) the informational function of this radio for the Indigenous communities in its listening reach; (b) that radio programming conveys family, community, and cultural knowledge bi-directionally both from and to its listening audience; and (c) that members of the audience were, in turn, prompted to action and engagement. In our discussion, we identify opportunities to improve the assessment of community-owned radio as a bidirectional resource for communities. Our work also advances a model of self-determined and stakeholder-driven evaluation for Indigenous community radio, with particular attention to the material (e.g., behavioral) impacts of radio messages and potential for radio to support communal and collective engagements desired by the communities it serves.