Are my girlfriends kids considered my step children or do we have to be married?

[Hal_Al]

You have to be married for them to be your step kids and "qualifying children" for tax purposes.

[bwa]

A stepchild is a child of your spouse from a former relationship.  No spouse = no stepchild.

[Hal_Al]

A stepchild is a child of your spouse or former spouse.  No spouse = no stepchild.

[bwa]

Thanks.