Threshold concepts (TCs) are increasingly used in health professions education (HPE) research. TCs are claimed to be conceptual gateways which are often traversed with substantial difficulty. In this paper, we report on a scoping review investigating the following research question: What is the scope and nature of the currently available research on threshold concepts in health professions education literature? We employed Arksey and O'Malley's model for scoping reviews. A search for literature on TCs in HPE research between 2003 and 2020 yielded 999 records of which 59 were included in the review. The data set was subject to quantitative descriptive analysis of article characteristics as well as qualitative thematic analysis of the scope of research on TCs. Among the 59 articles selected for review, there were 30 empirical, 26 conceptual and three reviews. A majority were published in 2015 or later. Almost half of the included articles attempted to identify possible TCs within HPE. Others investigated how TCs can be traversed or suggested how TCs could influence curriculum design. Some critically appraised the framework of TC. Although TCs are increasingly utilised in HPE, the present review identified how researchers came across methodological challenges related to identifying possible TCs and definitional challenges around identifying the essential characteristics of TCs. Before embracing TCs as the next go-to theory for learning in HPE, we acknowledge the need for methodological stringeny and rigour as well as more data to support TCs. Until then, any implementation of TCs in HPE curricula should be done cautiously.