The IRS regulations state that anyone who has income in excess of the varying filing thresholds must file a tax return. Each individual taxpayer is responsible for filing personal tax returns. That responsibility would include signing the return. However, if a child is unable to file a personal return or is not of sufficient understanding to grasp the purpose and consequences of their actions, it is the responsibility of the parent or legal guardian to file the return on the child's behalf.

A parent may sign a child's return, if the parent clearly indicates that they are doing so on behalf of the child taxpayer, if this is necessary to keep the child in compliance with tax law.