The aim of this study was to determine the validity and reliability of the Movement Environment Rating Scale (MOVERS), using data from 13 early childhood education and care (ECEC) settings. Test-retest reliability was calculated using ICCs, percentage agreement and weighted Kappa. Internal consistency was examined using Cronbach’s alpha. To examine concurrent validity between the MOVERS and Sustained Shared Thinking and Emotional Well-being Scale (SSTEW) scale and the Environmental Policy and Assessment Observation (EPAO), correlation coefficients were computed. Multi-level regression analyses were conducted to examine the criterion validity of MOVERS and children’s outcomes. ICC was 0.959 (p < 0.0001), weighted Kappa was 0.904 (p < 0.001), and percentage agreement was 69%–100%. Cronbach’s alpha of MOVERS was α = 0.94 and α = 0.89. Statistically significant correlations between MOVERS subscales and some SSTEW and EPAO sub-areas were reported. Item 4 (Body movement to support fine motor skills) of MOVERS and children’s fine motor skills was significantly correlated. This study shows that MOVERS is a reliable and valid scale that can, with training, be confidently used for research, audit, self-evaluation for practice improvement.