You can use Form 1040EZ (PDF) when claiming the earned income credit only if you do not have a qualifying child. However, you must meet several requirements to use Form 1040EZ (PDF). If you do not meet all of them, you must use Form 1040A (PDF) or Form 1040 (PDF). For additional information on the requirements, refer to Tax Topic 352, Which Form - 1040, 1040A or 1040EZ.

References:

• Form 1040 (PDF), U.S. Individual Income Tax Return
• Form 1040A (PDF), U.S. Individual Income Tax Return
• Form 1040EZ (PDF), U.S. Individual Income Tax Return for Single and Joint Filers with No Dependents
• Tax Topic 352, Which Form - 1040, 1040A or 1040EZ

Source: www.irs.gov