The ‘Brexit’ referendum represents a hostile shift in the United Kingdom's acculturative context. With its remain majority and pro‐migration political discourse, Scotland appears less hostile than the rest of the United Kingdom. We explored whether and how Brexit affected the mental health of European Union citizens living in Scotland. Thirty EU citizens took part in seven focus groups. Participants reported three main sources of acculturative stress: uncertainty, feelings of rejection and experiences of loss. These were associated with a range of negative emotional and mental states including anxiety, anger, shock and sadness. A minority reported severe difficulties including trauma, panic attacks and deterioration of existing physical and mental health conditions. Participants mobilised contrasts between Scotland and other parts of the United Kingdom to partially mitigate feelings of rejection. These findings indicate that the United Kingdom's hostile acculturative context has had important, enduring effects on the mental health of EU citizens in Scotland.