Background In children with cerebral palsy everyday movements such as walking, standing and using one's hands can be difficult to perform because of spasticity. Botulinum neurotoxin type A (BoNT‐A) are often used to reduce spasticity. The aim of this study was to describe how parents of children with cerebral palsy experienced the child's treatment with BoNT‐A, how the child was affected by the treatment and how spasticity affected the child. Methods A qualitative study in which 15 parents of children (6–13 years old) with cerebral palsy were interviewed about their experiences of the BoNT‐A treatment. The children had received several BoNT‐A treatments. An interview guide was used with topics: the child's functions before and after the treatment, the outcomes of the treatment and how they valued the BoNT‐A treatment. Content analysis was used to analyse the interviews. Results The analyses resulted in two themes: ‘When softness comes and goes’ and ‘Both want and do not want’. The reduction of spasticity – softness – was described to promote motor functions, and facilitate the next step in motor development. The children were described as being more active out of their own initiative and having a happier mood. Spasticity, described as stiffness, was described to make walking more strenuous as well as interfering with activities. The BoNT‐A injection procedure was perceived as troublesome and painful for the child, and sometimes traumatic for both children and parents. Conclusions Treatment with BoNT‐A was described as facilitating motor development and activity. The children's and the parents' negative experiences of the injection procedure should be addressed.