Given the risk for less optimal developmental attainment in children born to adolescent and young mothers, this study examined associations among child characteristics, parenting stress, and child risk for developmental delay from birth to age five years in mother–child dyads who attended a free-of-cost teen parenting program. Participants were 133 mothers and their target child classified in five age groups; mothers self-reported on the Parenting Stress Index-Short Form. While 68 % of children showed typical development across age groups, 32 % showed increased risk of developmental delay in five areas and overall using the Ages and Stages Questionnaire (ASQ-3). Maternal age did not increase the odds of child’s developmental delay. Multivariate analyses showed that the adjusted odds ratio of delay was higher among boys (vs girls), in Personal-social (aOR = 6.2) and Overall (aOR = 2.7). Compared to baseline age group (1–9 months), the odds of delay were higher in age 10–18 months for Personal-social (aOR = 5.3); in age 19–31 months for Communication (aOR = 13.5) and Overall (aOR = 6.3); and in age 32–44 months for Communication (aOR = 7.0). The odds of a delay were higher in children of mothers with higher parenting stress in three of the five developmental areas (Fine Motor, Problem Solving, Personal-social) and Overall. Children’s ages 3–4 and boys were associated with increased odds of delay in language and personal-social areas. Beyond screening for child developmental delay, surveillance for highly stressed mothers may be important to broaden risk reduction efforts among adolescent and young mother–child dyads served in primary care settings.