We aimed to identify characteristics of parents who do not voice developmental concerns when prompted by their children's nurse and/or primary care provider (PCP), despite reporting concerns on parent-completed questionnaires. We reviewed 376 medical records of children seen for a 9-month well-child visit in an urban pediatric clinic between September 2011 and December 2012 for sociodemographic variables hypothesized to affect parents' sharing of developmental concerns: the child's birth order and gender; parents' education level, employment, relationship status, and primary language; and family size and racial/ethnic background. The target population was parents who reported concerns on the Parents' Evaluation of Developmental Status (PEDS), a routinely administered, parent-completed screening questionnaire. We subdivided parents who reported concerns on the PEDS (N = 86) based on whether they voiced developmental concerns when prompted by their children's nurse and/or PCP. Two-sided Fisher's exact tests and logistic regression evaluated the relationship between sociodemographic variables and parents' voicing of developmental concerns. Only parent education approached significance, as parents with less than a high school education (<HS) were more likely to not voice concerns for their children's development than parents with at least a high school degree or equivalent (≥HS) (63% compared to 35%, p = .056). Univariate logistic regression analysis showed that parents with <HS were 3.238 (1.085-9.663, 95% CI, p = .035) times more likely to not verbally share developmental concerns than those with ≥HS. Parents with low educational attainment may be more likely to not verbally share their developmental concerns. For children of such parents, early detection of developmental delay may be strengthened by use of written questionnaires.