Although sertraline is considered one of the safest antidepressants in the lactation period, there are still few studies that assess its impact on child development. Therefore, this experimental study aimed to clarify the effect of sertraline on the neurobehavioral and reproductive development of male rats. Thus, 30 lactating rats were divided into 3 experimental groups (n = 10/group): CO- received filtered water, S10 and S20 groups that received, respectively, 10 and 20 mg/kg/day of sertraline. Treatment was performed by gavage, from postnatal days (PND) 1-20. During this period, the reflex and somatic development of rats were observed, as well as maternal behavior. On PND 21, mothers were euthanized and the organs were weighed. On PND 21, 45, and 100, one male from each litter was euthanized for histological and immunohistochemical (PCNA and WT1) analysis of the reproductive organs. The growth of body weight, the anogenital distance (AGD), the time to puberty, sperm quality, sexual behavior, neurobehavior, and natural fertility were also verified. Statistical analysis: One-way ANOVA or Kruskal-Wallis test (p ≤ 0.05). The results showed that mothers in the S20 group had an increase in thyroid weight. The male offspring exposed to sertraline had lower body weight (PND 7), lower AGD (PND 7 and 14), and delay in reflex development, in addition to histological alterations in the testis (PND 21). In adulthood, sperm quality was altered, without compromising natural fertility. Therefore, the present study found important alterations in the reflex and reproductive development of male rats exposed to sertraline during lactation.