Autistic masking is an emerging research area that focuses on understanding the conscious or unconscious suppression of natural autistic responses and adoption of alternatives across a range of domains. It is suggested that masking may relate to negative outcomes for autistic people, including late/missed diagnosis, mental health issues, burnout, and suicidality. This makes it essential to understand what masking is, and why it occurs. In this conceptual analysis, we suggest that masking is an unsurprising response to the deficit narrative and accompanying stigma that has developed around autism. We outline how classical social theory (i.e., social identity theory) can help us to understand how and why people mask by situating masking in the social context in which it develops. We draw upon the literature on stigma and marginalization to examine how masking might intersect with different aspects of identity (e.g., gender). We argue that although masking might contribute toward disparities in diagnosis, it is important that we do not impose gender norms and stereotypes by associating masking with a “female autism phenotype.” Finally we provide recommendations for future research, stressing the need for increased understanding of the different ways that autism may present in different people (e.g., internalizing and externalizing) and intersectionality. We suggest that masking is examined through a sociodevelopmental lens, taking into account factors that contribute toward the initial development of the mask and that drive its maintenance.