Camouflaging involves hiding one’s autistic characteristics in social situations and is associated with poorer mental health in autistic people. Various psychosocial factors are likely implicated in camouflaging and its impact on well-being. This mixed methods systematic review aimed to synthesize qualitative and quantitative research on psychosocial factors associated with camouflaging and its relationship with mental well-being in autistic and non-autistic people. Six electronic databases were searched. Following a convergent integrated approach, quantitative data were transformed and synthesized with qualitative data to perform thematic synthesis. Fifty-eight studies (40 qualitative, 13 quantitative, and five mixed methods) were included. We identified three themes on psychosocial correlates of camouflaging: (1) social norms and pressures of a largely non-autistic world, (2) social acceptance and rejection, and (3) self-esteem and identity; and four themes on psychosocial consequences of camouflaging for mental well-being: (1) a pragmatic way of exerting individual agency and control; (2) overlooked, under-supported, and burnt out; (3) impact on social relationships; and (4) low self-esteem and identity confusion. Camouflaging is a largely socially driven response associated with negative psychological and social consequences. A whole society approach is needed to promote a culture of acceptance and support autistic individuals to express their authentically autistic selves.