The safety of postnatal corticosteroids used for prevention of bronchopulmonary dysplasia (BPD) in preterm neonates is a controversial matter, and a risk-benefit balance needs to be struck. To evaluate 14 corticosteroid regimens used to prevent BPD: moderately early-initiated, low cumulative dose of systemic dexamethasone (MoLdDX); moderately early-initiated, medium cumulative dose of systemic dexamethasone (MoMdDX); moderately early-initiated, high cumulative dose of systemic dexamethasone (MoHdDX); late-initiated, low cumulative dose of systemic dexamethasone (LaLdDX); late-initiated, medium cumulative dose of systemic dexamethasone (LaMdDX); late-initiated, high cumulative dose of systemic dexamethasone (LaHdDX); early-initiated systemic hydrocortisone (EHC); late-initiated systemic hydrocortisone (LHC); early-initiated inhaled budesonide (EIBUD); early-initiated inhaled beclomethasone (EIBEC); early-initiated inhaled fluticasone (EIFLUT); late-initiated inhaled budesonide (LIBUD); late-initiated inhaled beclomethasone (LIBEC); and intratracheal budesonide (ITBUD). PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, World Health Organization's International Clinical Trials Registry Platform (ICTRP), and CINAHL were searched from inception through August 25, 2020. In this systematic review and network meta-analysis, the randomized clinical trials selected included preterm neonates with a gestational age of 32 weeks or younger and for whom a corticosteroid regimen was initiated within 4 weeks of postnatal age. Peer-reviewed articles and abstracts in all languages were included. Two independent authors extracted data in duplicate. Network meta-analysis used a bayesian model. Primary combined outcome was BPD, defined as oxygen requirement at 36 weeks' postmenstrual age (PMA), or mortality at 36 weeks' PMA. The secondary outcomes included 15 safety outcomes. A total of 62 studies involving 5559 neonates (mean [SD] gestational age, 26 [1] weeks) were included. Several regimens were associated with a decreased risk of BPD or mortality, including EHC (risk ratio [RR], 0.82; 95% credible interval [CrI], 0.68-0.97); EIFLUT (RR, 0.75; 95% CrI, 0.55-0.98); LaHdDX (RR, 0.70; 95% CrI, 0.54-0.87); MoHdDX (RR, 0.64; 95% CrI, 0.48-0.82); ITBUD (RR, 0.73; 95% CrI, 0.57-0.91); and MoMdDX (RR, 0.61; 95% CrI, 0.45-0.79). Surface under the cumulative ranking curve (SUCRA) value ranking showed that MoMdDX (SUCRA, 0.91), MoHdDX (SUCRA, 0.86), and LaHdDX (SUCRA, 0.76) were the 3 most beneficial interventions. ITBUD (RR, 4.36; 95% CrI, 1.04-12.90); LaHdDX (RR, 11.91; 95% CrI, 1.64-44.49); LaLdDX (RR, 6.33; 95% CrI, 1.62-18.56); MoHdDX (RR, 4.96; 95% CrI, 1.14-14.75); and MoMdDX (RR, 3.16; 95% CrI, 1.35-6.82) were associated with more successful extubation from invasive mechanical ventilation. EHC was associated with a higher risk of gastrointestinal perforation (RR, 2.77; 95% CrI, 1.09-9.32). MoMdDX showed a higher risk of hypertension (RR, 3.96; 95% CrI, 1.10-30.91). MoHdDX had a higher risk of hypertrophic cardiomyopathy (RR, 5.94; 95% CrI, 1.95-18.11). This study suggested that MoMdDX may be the most appropriate postnatal corticosteroid regimen for preventing BPD or mortality at a PMA of 36 weeks, albeit with a risk of hypertension. The quality of evidence was low.