Background: Identifying parental perceived barriers might contribute to strategies to promote physical activity in children. This study aimed to observe parental perceived barriers for 6- to 10-year-old children’s participation in organized sports and understand to what extent the socioeconomic status, the place of residence, and children’s sex, age, and sport participation affect those perceived barriers. Methods: Data were collected from 834 parents of 6- to 10-year-old children living in the Portuguese Midlands, using a multiple-choice questionnaire. Parents reported the perceived barriers to children’s sport activities, such as time, health, transportation, costs, safety, facilities, weather, tiredness, and lack of interest. Children’s and sociodemographic characteristics were also collected. Results: Time and costs were the most reported barriers by parents. Barriers to access were mostly reported by parents of girls and younger children, parents of inactive children, and families living in an urban setting and in socioeconomic disadvantage. Perceived barriers differed according to both children’s and sociodemographic characteristics, highlighting the need to reduce costs and increase the variety of sports/facilities, particularly in families with girls, younger children, and those with lower incomes from more urbanized areas. Conclusions: The present findings should be considered in future planning and interventions to effectively promote physical activity in children.