This article introduces Youth Participatory Science (YPS) as an approach to science teaching and grassroots knowledge production that draws from traditions of youth participatory action research (YPAR) and citizen science. YPS is differentiated from YPAR by its emphasis on the tools and methods of the so-called natural sciences while it extends citizen science in important ways by prioritizing youth, pedagogy, and democratizing participation in all phases of knowledge production. This article contributes to a conceptual definition of YPS and articulates the affordances and limitations of distinguishing it from YPAR and citizen science. It then introduces a curriculum framework that synthesizes approaches to planning for critical pedagogy and science education with the intention of supporting teachers to navigate the barriers to enacting YPS in secondary science classrooms.