The benefits of routine gastric suctioning or lavage in neonates remain uncertain, despite the common practice worldwide. To investigate the potential advantages and harms, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) examining the effects of these procedures in healthy or meconium-stained neonates at birth. We systematically searched PubMed, Scopus, Embase, Ovid, and the Cochrane Library databases from inception to February 9, 2023. We included only RCTs assessing the outcomes of gastric suction or lavage in neonates at birth. We calculated risk ratio (RR) and weighted mean differences with 95% confidence intervals (CIs) using a random-effects model. The primary outcomes were gastrointestinal symptoms including vomiting, retching, feeding intolerance, and secondary aspiration. The secondary outcomes included time to initiation of breastfeeding and potential adverse procedure-related events. Twelve RCTs with a total of 4,122 neonates were analyzed. All the studies compared neonates who received gastric suction or lavage with those who received usual care. Gastrointestinal symptoms were significantly reduced in neonates receiving gastric suction or gastric lavage compared with the control group (RR, 0.75; 95% CI, 0.63–0.89). Gastric lavage was beneficial for infants with meconium-stained amniotic fluid (RR 0.71; 95% CI, 0.60–0.84), while gastric suction had no significant benefit in reducing gastrointestinal symptoms in infants without meconium-stained amniotic fluid (RR 0.91; 95% CI, 0.61–1.37). Our findings suggest that gastric suction or lavage may reduce gastrointestinal symptoms in neonates; however, these procedures may only benefit infants born with meconium-stained amniotic fluid. Vigorous newborns without meconium-stained amniotic fluid may not benefit from these procedures. Furthermore, gastric suction may lead to adverse outcomes such as apnea and bradycardia.Registration: This study was registered in the PROSPERO International prospective register of systematic reviews in health and social care (CRD42023247780).