U.S. citizens and permanent residents can sponsor their family members for immigration to the United States. Citizens can sponsor their spouses, children, parents, and brothers & sisters. Permanent residents can sponsor their spouses and unmarried children. Each category of children has its own visa classification and waiting period, which can be as long as several years.
The approximate wait times, shown above, are for comparison purposes only. You may check the visa availability of a particular visa category for your country of origin. See Priority Date & Visa Availability.
Permanent residents cannot petition for the immigration of their married children, parents, or brothers & sisters. They can do that after they naturalize (become a citizen).
Note that derivative beneficiary spouses and children (under 21 and unmarried), who accompany or "follow to join" principal immigrants in other immigrant classes (such as employment-based classes), do not fall within the categories shown above.