<p>The teaching of photosynthesis in secondary schools often follows a mechanistic, decontextualized approach that lacks integration with the broader implications of this biochemical process on societal and sustainability issues. Contemporary science education frequently overlooks the significance of photosynthesis for life on Earth and human society. This study aims to identify a <i>Photosynthesis Literacy Framework</i>—a research-based curricular framework designed to promote a more relevant and engaging photosynthesis education that fosters scientific literacy. A Delphi study was conducted to determine pertinent content themes concerning photosynthesis and its essential role in life and human society. A panel of 29 experts, including 12 science educators, nine green scientists, and eight sustainability scientists, reached consensus after three iterative rounds. The study identified four overarching themes, comprising 25 content categories with aligned learning objectives, connected to the three visions of scientific literacy. These themes are: <i>Photosynthesis as a natural science phenomenon; Photosynthesis as a driving force in biological and geological processes and cycles; Photosynthesis and its importance to sustainability; </i>and<i> Photosynthesis from a societal perspective</i>. We propose that the Photosynthesis Literacy Framework be implemented in secondary science education to promote photosynthesis literacy, which plays a vital role in developing informed and responsible citizenship.</p>