This paper synthesized 66 studies both in English and Chinese concerning projection in Systemic Functional Linguistics with a meta-analysis and synthesis approach. Our data show that projection in Systemic Functional Linguistics (hereafter SFL) is a burgeoning field with expanding focused areas from different settings after several decades of development. Five major domains of research have been identified, namely, theoretical discussions, language description, language education, translation studies, and professional communication. Studies in these areas demonstrate that the notion of projection is of great theoretical significance. It is also a useful analytical tool in investigating both written and spoken discourse. However, it is found that interpersonal projection remains an elusive concept, and projection below the clause rank has just begun to gain attention. Projection in professional communication, translation studies and multimodality is underinvestigated.Projection is typically realized as a clause complex consisting of a projecting clause and a projected clause. For example, in he said he would go, the projecting clause is 'he said' whereas the projected clause is 'he would go'. The notion of projection, however, is distinctive in the sense that it is a semantic category that is general enough to cover