This qualitative study aims to explore and gain an in-depth understanding of the knowledge and perceptions of mothers living in Greater Western Sydney (GWS), one of Australia’s most socio-economically disadvantaged regions, regarding the factors that influence oral health of young children. Mother–child dyads (n = 45) were purposively selected from a population-based cohort study in GWS. Semi-structured in-depth interviews were audio-recorded, transcribed verbatim, and subsequently analyzed using thematic analysis. Five main themes emerged from the interviews: (1) beliefs about child oral health and first set of teeth; (2) awareness and attitudes towards oral health services; (3) identification of caries risk and protective factors; (4) broader cultural and social class influences on childhood oral health practices; and (5) the influence of parental self-confidence, self-efficacy, and perceived control. Overall, mothers reported having limited knowledge and awareness on the importance of baby teeth, child’s first dental visit, and seeking oral health care. Oral health and preventative practices in children were reported to be influenced by past dental experiences, culture and social class, and parental factors. The empirical findings of this study bring our attention to the critical factors that influence child oral health and the opportunities for co-creating child oral health promotion by targeting mothers.