Married and Living Apart with Dependent Child
Some married taxpayers who live apart from their spouses and provide for dependent children may be "considered unmarried" for tax purposes. These taxpayers are permitted to file as Head of Household and receive the benefit of lower tax amounts if they:
For these married taxpayers, "qualifying child" includes biological, adopted, foster, and stepchildren, but does not include grandchildren, brother, sister or their descendants (for example, niece, nephew). Only unmarried taxpayers may be able to use a grandchild, niece or nephew as a qualifying child for Head of Household status.