If the parents are separated or divorce, the custodial parent is responsible for filling out the FAFSA or the Free Application for Federal Student Aid. The custodial parent for the purposes of federal student aid is the parent with whom you lived the most during the past 12 months. (The twelve-month period is the twelve-month period ending on the FAFSA application date, not the previous calendar year.) Note that this is not necessarily the same as the parent who has legal custody. If you did not live with one parent more than the other, the parent who provided you with the most financial support during the past twelve months should fill out the FAFSA. This is probably the parent who claimed you as a dependent on their tax return. If you have not received any support from either parent during the past 12 months, use the most recent calendar year for which you received some support from a parent.

Biological parents who never married are treated the same as parents who are divorced. However, that any child support and/or alimony received from the non-custodial parent must be included on the FAFSA.