Test preparation has garnered considerable attention in second language (L2) education due to the significant implications that successful performance on a language test may have for academic advancement, future career opportunities, and immigration prospects. Meanwhile, an overemphasis on test preparation has been criticized for encouraging the cultivation of construct-irrelevant test-taking strategies at the expense of developing general language proficiency. To systematically explore how test preparation has been investigated in the literature, we conducted a scoping review of 66 studies on L2 test preparation. Specifically, this study examined the key characteristics of publications on test preparation, the main themes explored, the study and participant characteristics, as well as the essential aspects of their research methodologies. The results of this review revealed various trends in the literature on L2 test preparation, such as the exclusive focus on English as the target language, the lack of diversity in stakeholders as participants, the dominance of international language tests, and the paucity of experimental studies that utilize advanced statistical techniques. In addition to interpreting the results of our analysis, we discuss the implications of this scoping review and outline several directions for future research on test preparation.