Background: Despite extensive prevention programs, dental hygiene remains inadequate, particularly among children under the age of six, and early childhood caries (ECC) are still a concern. Oral hygiene behavior and preventive practices seem difficult to change at a family level. Aim. The present study aimed to better understand the reasons behind this behavior and to identify the different barriers to the implementation of adequate preventive measures. Methods: A qualitative study was conducted in the pediatric dentistry service of the Montpellier University Hospital (France) in 2019. A thematic analysis concerning three domains was performed: family environment, dental literacy, and oral hygiene. Results. The main barriers encountered by the parents were, respectively, (1) a weakness in the organization of familial life, together with a low-medium family income and a lack of authority, (2) ignorance of the necessity of treating carious primary teeth, and (3) a lack of time for brushing or supervising their children’s teeth. Conclusion: These results showed that oral hygiene and primary teeth care could not be easily achieved in the family environment of the participants, and oral health strategies should be focused not only on children but also on their parents.