Inclusion Criteria: - Male and female adolescents 12 to less than 18 years of age - Recipients of a renal allograft from a living or deceased donor transplanted at least 6 calendar months prior to enrollment - Receiving a stable regimen of a calcineurin inhibitor (CNI), with mycophenolate mofetil (MMF) or enteric-coated mycophenolate sodium/mycophenolate mofetil (EC-MPS/MPA), with or without daily corticosteroids for ≥ 30 days prior to randomization - Clinically stable renal function during the 12-week period prior to screening, in the opinion of the investigator and based on protocol-defined criteria for proteinuria and estimated glomerular filtration rate (eGFR) - Serologic evidence of past exposure to Epstein-Barr virus (EBV) and current absence of EBV DNA replication at or prior to renal transplantation and during the Screening period - Completion of an initial course of SARS-CoV-2 vaccination per local standard of care, a minimum of 6 weeks prior to enrollment Exclusion Criteria: - Recipients with EBV serostatus negative or unknown at screening or at transplant - Treatment for biopsy-proven acute rejection (BPAR) of any degree of severity within 6 calendar months prior to enrollment - Biopsy-confirmed antibody-mediated acute rejection at any time with the current allograft - Banff 97 grade IIA or higher acute cellular rejection (or equivalent), or treatment with plasmapheresis or rituximab for any acute rejection at any time with the current allograft - Current evidence or past history of active or inadequately treated latent tuberculosis (TB) infection - Previously treated with belatacept or previously enrolled in a belatacept trial with their present allograft Other inclusion/exclusion criteria apply