Background/Objectives: The Parenting Sense of Competence (PSOC) scale is one of the most widely used instruments to assess perceived parental competence, understood as the degree to which parents feel capable of adequately fulfilling their parental role. Despite its widespread use, studies seeking to determine PSOC normative scores are scarce, especially in specific populations such as mothers with infants younger than 9 months, which limits the interpretation of its scores in applied contexts. This study establishes PSOC normative scores in a nonclinical sample of 522 Spanish mothers with infants aged between 3 and 37 weeks who attended a public early intervention program. Methods: Regression and ANOVA analyses were performed to examine the effect of infant and maternal age, as well as educational level and occupation, on the dimensions of Efficacy, Satisfaction, and Total score of the PSOC. Results: The results show a significant decline in parental competence starting when their infants reach 9 months of age, and lower levels of self-efficacy in mothers over 35 years of age. No significant differences were found according to the educational level or occupation of the mothers. Normative scores are presented by percentiles, offering specific criteria for this stage of child development. Z- and T-scores are included, useful for standardized comparisons between subscale and studies. Conclusions: These findings provide useful information for early detection and psychoeducational interventions within the framework of early intervention.