From the refrigerator mother theory to more recent comparisons to ‘warrior-heroes’, mothers of children with autism spectrum disorders have been historically categorised as emotionally remarkable. Drawing on my ethnographic fieldwork in Portugal, I explore in this article how mothers politically mobilise emotions, characteristics, and acts usually associated with good mothering, such as maternal love, dedication, and sacrifice. While these socially expected phenomena have been addressed as instruments of the relegation of women to motherhood and care labour, I propose a novel look at the value of affectivity in discourses and practices of care and advocacy. I argue that mothers strategically embody and employ their affectivity as political capital to validate their role as expert caregivers and advocates, creating new opportunities to access leading positions within the autism advocacy movement.