Ohio Income Tax Filing Deadlines by Tax Year The majority of deadlines listed here are for Tax Year 2023. Some apply to upcoming Tax Years and some are IRS or Federal deadlines. Deadline Type Description April 15, 2024 Tax Year 2023Income Tax Return Prepare and e-File an IRS (Due Date April 15, 2024) and Ohio State Income Tax Return (Due Date April 15, 2024) until October 15, 2024. - eFileIT April 15, 2024 2023 Income Tax Extension Ohio Income Tax Extension Details October 15, 2024 Tax Year 2023Income Tax Return after the April 15, 2024 Ohio Tax Extension Last day to e-File a 2023 Ohio State Income Tax Return for Tax Extension Filers and late eFilers. You can only e-File (to file by paper see below) Ohio Income Tax Return together with an IRS Tax Return. eFileIT October 15, 2024 via mail-in Forms.Forms incl. Mailing Address are listed below. Tax Year 2023Income Tax Return after the April 15, 2024 Ohio Tax Extension Deadline for taxpayers who got an OH Tax Extension to file their OH Income Tax Return by mail-in Forms - the Forms incl. mailing addresses are listed below - is October 15, 2024. (Optionally, the eFileIT deadline is Oct. 15, 2024). Instructions on how to only - without the IRS return - prepare and file an Ohio State Income Tax Return on eFile.com. Complete and Mail In Now Tax Amendment for all Tax Years Detailed Instructions on how to prepare and mail in an Ohio State Income Tax Return Amendment. IRS Due Dates IRS Tax Return, Extension, Amendment Deadlines Detailed current and future Federal or IRS Income Tax Deadlines 2023, 2024, etc. Other State Tax Return, Extension, Amendment Deadlines Select respective State Tax Return Deadlines. 2023, 2024, etc. IRS Federal Income Tax Return, Amendment, Extension Deadlines 2023, 2024 Tax Year Income Tax Return Deadlines April 15, 2028 2024 Ohio Income Tax Return Refund.IRS Tax Return Refund Claim Deadline The last day to file - you will not face late filing penalties - and claim your 2024 Ohio Income Tax Return Refund. This deadline does not apply if you owe 2024 Income Taxes. TurboTax® is a registered trademark of Intuit, Inc. H&R Block® is a registered trademark of HRB Innovations, Inc.