The purpose of this manuscript was to develop and test the psychometric properties of the Environmental Restriction Questionnaire (ERQ) a parent-reported questionnaire for measuring perceived environmental restrictions for young children participation. Reliability and homogeneity were tested by Cronbach's alpha and inter-item correlations. Construct validity was computed by factor analysis and known group differences analysis. Convergent and divergent validities were calculated by correlation with the Children Participation Questionnaire (CPQ). Participants were 290 children and their parent. Seventy-five children who were referred to occupational therapy evaluation as consequence of moderate developmental disabilities and 215 children without any disability (mean age [plus or minus] standard deviation for total sample, 5 y, 3 mo [plus or minus] 0.65 y; range, 3 y, 11 mo to 6 y, 10 mo). The ERQ has good internal reliability. Cronbach's alpha for the ERQ measures ranged between 0.75 and 0.91, indicating adequate homogeneity. Factor analysis yielded three factors that explained almost 48% of the total variance. Significant differences were found between known groups. Convergent and divergent validity were supported by various correlations with the Children Participation Questionnaire (CPQ). The ERQ has demonstrated good psychometric properties and can be used as a reliable and valid measure to assess perceived environmental restriction at the age of 4-6 y. (Contains 5 tables.)