Last reviewed September 2026
Overview: F3 covers married sons and daughters of U.S. citizens. F4 covers siblings of U.S. citizens, and requires the petitioning citizen to be at least 21 years old. F4 is generally the most backlogged family preference category, often carrying waits measured in decades for high-demand countries, considerably longer than F3's typically shorter, though still substantial, wait.
Who qualifies under F3
F3 covers the married son or daughter of a U.S. citizen, at any age, along with that son or daughter's spouse and unmarried minor children as derivative beneficiaries.
Who qualifies under F4
F4 covers the brother or sister of a U.S. citizen, but only where the petitioning citizen is at least 21 years old, along with the sibling's spouse and unmarried minor children as derivatives.
Why F4 typically carries the longest wait of any family category
F4 receives a smaller annual allocation relative to demand than most other family categories, and sibling relationships are a step further removed than parent-child relationships in the priority Congress assigned across the preference system, which is part of why F4 waits, particularly for high-demand countries, have historically run longer than any other family preference category.
How derivative family members factor into each category
Both F3 and F4 allow the principal beneficiary's spouse and unmarried minor children to immigrate together as derivatives once a visa becomes available, though those derivative children remain subject to the same Child Status Protection Act age calculations as any other derivative beneficiary.
Why the citizen petitioner's age matters for F4 specifically
Unlike most family categories, F4 has an age floor for the petitioner: a U.S. citizen cannot petition for a sibling until they turn 21, which can delay when an eligible petition can even be filed in situations where the citizen sibling is still a minor.
Setting realistic expectations for either category
Given how long both categories, and F4 in particular, can take depending on the beneficiary's country of birth, checking current Visa Bulletin movement for the specific category and country is essential to setting a realistic timeline rather than relying on a general sense of how family immigration works.
Official sources
Related reading
- The Family Preference Categories
- F1 vs. F3: Unmarried vs. Married Sons and Daughters of U.S. Citizens
TR Immigration is an independent immigration information platform. It is not a law firm. Nothing here is legal advice, an eligibility determination, or a prediction about your case. Rules and fees change often, so confirm anything you rely on against the official page it links to.