The Immigration & Nationality Act requires a U.S. citizen to be 21 twenty-one years of age in order to be eligible to sponsor a parent or sibling for an immigrant visa. Â For parents, the immigrant visa is immediately available. Â For siblings, there is a long wait (currently around 11 years).
For all other immigrant visas - including spouses and children - there is no age requirement. Â However, every sponsor for an immigrant visa must be 18 years old in order to execute a valid affidavit of support. Â Thus, for all practical purposes, you must be 18 years old to sponsor your spouse or children for an immigrant visa and 21 to sponsor your parents or siblings.