Even if you're not a kid anymore, your parents can claim you as a dependent. Dependents include both "qualifying children" and "qualifying relatives." Both categories allow a parent -- or a grandparent, foster parent, step parent or sibling -- to claim a dependent's exemption for you when you're older than 18. You do have to meet all the IRS tests for dependent status.
You stay a qualifying child up until you turn 19, not 18, provided you're younger than the person claiming you. After 19, you can stay a dependent until you turn 24 if you're a full-time student. If you become permanently and totally disabled, your parents -- or whoever -- can claim you indefinitely. You have to live with whoever claims you for at least half the year and you must pay less than half your expenses.
To become a qualifying relative, you can't earn more than the personal exemption amount for the year -- $3,800 as of 2012. The person claiming you has to pay half your total support, which can include room, board and medical bills. If you're claimed by a family member such as your father, sister, uncle or in-law, you don't have to live in their house. If a non-relative claims you -- your girlfriend's parents, for instance -- you have to live with them year-round.
The residency requirement -- the amount of time you have to live with whoever claims you as a dependent -- comes with lots of exceptions. Suppose you're a full-time college student and only home for Christmas and the summer. That doesn't disqualify you as a dependent if your parents' home is still your primary residence. Military service, vacations and hospital stays don't rule you out either. If you die during the year, but qualified as a dependent up to your death, whoever claims the exemption can still do so for the last year of your life.
Even if you meet every other requirement, some life situations get you crossed off the list as a dependent. If you're not an American citizen, resident alien or national, or a resident of Canada or Mexico, nobody can claim you as a dependent. Once you get married and file a joint return with your spouse, you're not anyone's dependent, even if you're younger than 19. If your parents split up, only one of them gets to claim you as a qualifying child.
A graduate of Oberlin College, Fraser Sherman began writing in 1981. Since then he's researched and written newspaper and magazine stories on city government, court cases, business, real estate and finance, the uses of new technologies and film history. Sherman has worked for more than a decade as a newspaper reporter, and his magazine articles have been published in "Newsweek," "Air & Space," "Backpacker" and "Boys' Life." Sherman is also the author of three film reference books, with a fourth currently under way.