DHA is an important omega-3 PUFA that confers neurodevelopmental benefits. Sufficient omega-3 PUFA intake has been associated with improved mood-associated measures in adult humans and rodents, but it is unknown whether DHA specifically influences these benefits. Furthermore, the extent to which development and puberty interact with the maternal diet and the offspring diet to affect mood-related behaviors in adolescence is poorly understood. We sought to address these questions by 1) feeding pregnant rats with diets sufficient or deficient in DHA during gestation and lactation; 2) weaning their male offspring to diets that were sufficient or deficient in DHA; and 3) assessing depression-related behaviors (forced swim test), plasma biomarkers [brain-derived neurotrophic factor (BDNF), serotonin, and melatonin], and brain biomarkers (BDNF) in the offspring before and after puberty. No dietary effects were detected when the offspring were evaluated before puberty. In contrast, after puberty depressive-like behavior and its associated biomarkers were worse in DHA-deficient offspring compared with animals with sufficient levels of DHA. The findings reported here suggest that maintaining sufficient DHA levels throughout development (both pre- and postweaning) may increase resiliency to emotional stressors and decrease susceptibility to mood disorders that commonly arise during adolescence.