Few qualitative studies have explored the lives of autistic women diagnosed in adulthood, despite this knowledge being essential to inform awareness of the intersection of autism and gender. This systematic review was undertaken to synthesise available qualitative evidence on the lived experience of autistic women diagnosed in adulthood. The accounts of 50 women from nine qualitative studies were synthesised using thematic analysis and four super-ordinate themes were identified: wanting to ‘fit in’; making sense of past experiences; developing a new ‘autistic identity’; and barriers to support. The autistic women spent many years without a diagnosis or autism-specific support, felt misunderstood, and experienced social exclusion. Following their diagnosis, they reframed these experiences into new ‘sense-making narratives’, used social media to contact other autistic people, and developed neurodiverse-affirming autistic identities. The studies suggested that health and social care professionals were not always able to recognise, refer, diagnose, and support autistic women effectively.