This study compared fundamental movement skills (FMS) in children from schools on the lower and upper levels of socioeconomic status. Data were collected from 228 schoolchildren across five schools in Ireland. There were 147 children from schools of social disadvantage (Mage = 7.67 [SD = 0.62] years; 55% boys) and 81 children from schools considered in the normal range for socioeconomic development (Mage = 7.34 [SD = 0.26] years; 56% boys). FMS were assessed using the Test of Gross Motor Development–2. Mixed models were used to estimate differences in FMS, while controlling for the nested structure of the data and for sex, age, body mass index, and class size. There was a substantial sex×school interaction, with girls from schools of social disadvantage exhibiting greater object-control skills proficiency than their counterparts in schools on the upper tertiles of socioeconomic development (standardized effect size = 0.66 [±95% confidence limits, ±0.50]; p = .02). The suggestion that children from social disadvantage are delayed in FMS is unsupported in this cohort. Differences in the structure of physical education and types of sports undertaken by children in schools of social disadvantage in Ireland are considered as explanations for this departure from previous studies.