The aim of this study was to investigate the relation between sitting posture of diplegic spastic cerebral palsied children and the quality of life of their mothers. Twenty two children with the diagnosis of diplegic spastic cerebral palsy and their mothers were included in the study. The functional level of children were classified according to the Gross Motor Function Classification System (GMFMCs). Sitting Assessment Scale (SAS) was used to evaluate sitting posture. Nottingham Health Profile (NHP) was used to assess the quality of life of mothers. Spearman correlation analysis was used to investigate the relation between sitting posture of children and quality of life of mothers. The mean age of children and mothers were 6.3 ± 4.6 years, 35.7 ± 8.6 years, respectively. The median GMFMCs level was 4. The mean SAS score was 13.2 ± 3.4 in children and, mean NHP score was 164.2 ± 106.7 in mothers. There was a significant correlation between SAS score and NHP score (rho=-0,622, p < 0.05). Proper sitting posture is important for feeding, carrying and caring of a child. Improvements in sitting posture of children with cerebral palsy may have favourable effects on mothers’ and caregivers’ quality of life.