<p>Group B (GBS) remains the most common cause of neonatal early-onset sepsis among term infants and a major cause of late-onset sepsis among both term and preterm infants. The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists published separate but aligned guidelines in 2019 and 2020 for the prevention and management of perinatal GBS disease. Together, these replace prior consensus guidelines provided by the Centers for Disease Control and Prevention. Maternal intrapartum antibiotic prophylaxis based on antenatal screening for GBS colonization remains the primary recommended approach to prevent perinatal GBS disease, though the optimal window for screening is changed to 36 0/7 to 37 6/7 weeks of gestation rather than beginning at 35 0/7 weeks' gestation. Penicillin, ampicillin, or cefazolin are recommended for prophylaxis, with clindamycin and vancomycin reserved for cases of significant maternal penicillin allergy. Pregnant women with a history of penicillin allergy are now recommended to undergo skin testing, because confirmation of or delabeling from a penicillin allergy can provide both short- and long-term health benefits. Aligned with the American Academy of Pediatrics recommendations for evaluating newborns for all causes of early-onset sepsis, separate consideration should be given to infants born at less than 35 weeks' and more than or equal to 35 weeks' gestation when performing GBS risk assessment. Empiric antibiotics are recommended for infants at high risk for GBS early-onset disease. Although intrapartum antibiotic prophylaxis is effective in preventing GBS early-onset disease, currently there is no approach for the prevention of GBS late-onset disease.</p>