Camouflaging is hypothesized to play an important role in developing mental health difficulties. But this might not be true for everyone. It remains unclear for whom camouflaging is associated with mental health. In this preregistered study (AsPredicted #45095), we investigated whether (1) camouflaging and mental health were associated and (2) we could detect subgroups with a different association between camouflaging and mental health. For this study, 352 autistic adults aged 30-84 years filled in, among others, the Dutch Camouflaging Autistic Traits Questionnaire to measure camouflaging and the Symptom Checklist-90 Revised to measure mental health difficulties. We found a moderate correlation between camouflaging and mental health difficulties (r = 0.45). However, there was only a strong association between camouflaging and mental health in a small subgroup, while the association was small in most autistic adults. For varying levels of negative affect and (to a lesser extent) autism traits, the association between camouflaging and mental health differed, but not for biological sex, age, or educational level. Thus, while one should be careful with group-based conclusions regarding the (negative) impact of camouflaging, camouflaging can be important to consider in clinical practice, especially for people with a substantial level of negative affect.