Home / Tax Resources / State And Federal / Efile-Oklahoma-Tax-Return Efile Oklahoma State Tax Returns Start For Free Oklahoma State Tax Filing Information The eSmart Tax online tax return filing solution makes it easy to efile your Oklahoma state tax return using the correct state tax forms. Prepare your full-year resident Oklahoma state tax return alongside your federal tax return for your convenience. The regular deadline to file an Oklahoma state income tax return is April 15, but Oklahoma offers a special deadline date for electronically filed returns. If you efile your return, you can file on or before April 20. Find additional information about Oklahoma state tax forms, Oklahoma state tax filing instructions, and government information. eSmart Tax supports the following Oklahoma Tax Forms (Click here to download Oklahoma tax forms) Oklahoma Form 511 Individual Resident Income Tax Return Oklahoma Form 511-EF Oklahoma Individual Income Tax Declaration for Electronic Filing Oklahoma Form 511-V Individual Income Tax Payment Voucher Liberty eSpecial: $50 Off Tax Prep! State OK Website and Contacts State Website http://www.tax.ok.gov/incometax.html Taxpayer Assistance: (405) 521-3160 or (800) 522-8165 (In-State Only) Refund Status (Automated Response): (405) 521 -3160 Special Processing Type: Availability: State-only tax return: Supported Decedent Return: Supported Return with foreign address: Supported State OR Amount Owe Payment Option You have the following options to pay your tax: Pay by Direct Debit from bank account. You need to make sure your bank supports direct debit. OK support both Direct Debit and Deposit Mail in a check. You need to attach Payment Voucher (Form 511-V) Mail check to: Oklahoma Tax Commission Income Tax PO Box 26800 Oklahoma City, OK 73126-0800 Enclose a check or money order payable to "Oklahoma Tax Commission". Send e-payment through state website. Send credit card payment through third-party website. PIN Availability: Type: Notes: Supported Same as federal N/A State Return Type Residency: Return Type: Notes: Resident OK-511 N/A State OK Overpayment Option You have the following options: Apply your refund amount to next year's tax payment. Contribute your refund amount to charity. Receive your refund by check through mail. Receive your refund by direct deposit to your bank account.