Massachusetts Form 11A is an income tax form used by Massachusetts taxpayers to calculate their state income tax liability. It is used by individuals, estates, trusts, and corporations. The form is divided into four sections: (1) Taxpayer Identification Information, (2) Massachusetts Taxable Income Computation, (3) Credits and Deductions, and (4) Other Taxes. Taxpayers must complete each section of the form in order to calculate their Massachusetts income tax liability. There are two types of Massachusetts Form 11A: Form 11A for Nonresidents and Part-Year Residents, and Form 11A for Full-Year Residents.