Emerging evidence suggests that parents’ nutritional status before and at the time of conception influences the lifelong physical and mental health of their child. Yet little is known about the relationship between diet in adolescence and the health of the next generation at birth. This study examined data from Norwegian cohorts to assess the relationship between dietary patterns in adolescence and neonatal outcomes. Data from adolescents who participated in the Nord-Trøndelag Health Study (Young-HUNT) were merged with birth data for their offspring through the Medical Birth Registry of Norway. Young-HUNT1 collected data from 8980 adolescents between 1995 and 1997. Linear regression was used to assess associations between adolescents’ diet and later neonatal outcomes of their offspring adjusting for sociodemographic factors. Analyses were replicated with data from the Young-HUNT3 cohort (dietary data collected from 2006 to 2008) and combined with Young-HUNT1 for pooled analyses. In Young-HUNT1, there was evidence of associations between dietary choices, meal patterns, and neonatal outcomes, these were similar in the pooled analyses but were attenuated to the point of nonsignificance in the smaller Young-HUNT3 cohort. Overall, energy-dense food products were associated with a small detrimental impact on some neonatal outcomes, whereas healthier food choices appeared protective. Our study suggests that there are causal links between consumption of healthy and unhealthy food and meal patterns in adolescence with neonatal outcomes for offspring some years later. The effects seen are small and will require even larger studies with more state-of-the-art dietary assessment to estimate these robustly.