Prematurity, observed in 15 million births worldwide each year, is a clinical conditionthat is a major cause of neonatal mortality and morbidity in the short and long term. Preterm infantsare at high risk of developing respiratory problems, sepsis, and other morbidities leading to neurodevelopmentalimpairment and neurobehavioral disorders. Perinatal glucocorticosteroids have beenwidely used for the prevention and treatment of adverse outcomes linked to prematurity. However,despite their short-term benefits due to their maturational properties, some clinical trials have shownan association between steroids exposure and abnormal brain development in infants born preterm.Neuroinflammation has emerged as a preeminent factor for brain injury in preterm infants, and themajor role of microglia, the brain resident immune cells, has been recently highlighted. Consideringthe role of microglia in the modulation of brain development, the aim of this review is to summarizethe effects of endogenous and exogenous glucocorticosteroids on brain development and discuss thepossible role of microglia as the mediator of these effects.