Many people believe that receiving a Green Card through a sibling sponsorship automatically grants U.S. citizenship, but this is a myth. A Green Card only provides lawful permanent residency, not citizenship. Once siblings obtain their Green Card, they must wait at least five years to apply for naturalization, or three years if they are married to a U.S. citizen. During this period, they must meet all eligibility requirements, including continuous residence in the U.S., physical presence, and good moral character. Citizenship is a separate process requiring an application, interview, and passing the naturalization test.