Delaware Income Tax Filing Deadlines by Tax Year

Delaware state income tax returns for the 2023 tax year can be prepared and e-filed now along with an IRS or federal tax return (or you can learn how to only prepare and eFile a Delaware state return). Find IRS or federal tax return deadline details.

Delaware Income Tax Filing Deadlines

The majority of deadlines listed here are for Tax Year 2023; some apply to upcoming years and some are IRS or federal deadlines.

Deadline

Type

Description

Prepare, eFile, Download
DE + IRS Tax Return

Detailed eFile.com Service Overview

Start Federal and Delaware Tax Returns

April 30, 2025

Tax Year 2023
Income Tax Return

Prepare and e-File an IRS (Due Date April 18, 2023) and Delaware State Income Tax Return (Due Date April 30, 2025) until October 15, 2025 - eFileIT.

April 30, 2025

2023 Income Tax Extension

Delaware Income Tax Extension Details

October 15, 2025

Tax Year 2023
Income Tax Return after the April 30, 2025 Delaware Tax Extension

Last day to e-File a 2023 Delaware State Income Tax Return for Tax Extension Filers and late eFilers. You can only e-File (to file by paper see below) Delaware Income Tax Return together with an IRS Tax Return - eFileIT.

October 15, 2025 via mail-in Forms.
Forms incl. Mailing Address are listed below.

Tax Year 2023
Income Tax Return after the April 30, 2025 Delaware Tax Extension

Deadline for taxpayers who got a DE Tax Extension to file their Delaware Income Tax Return by mail-in Forms - the Forms incl. mailing addresses are listed below - is October 15, 2025. (Optionally, the eFileIT deadline is Oct. 15, 2025). Instructions on how to only - without the IRS return - prepare and file a Delaware 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 a Delaware State Income Tax Return Amendment.

IRS Due Dates

IRS Tax Return, Extension, Amendment Deadlines

See detailed current and future Federal or IRS Income Tax Deadlines.

2023, 2025, etc.

Other State Tax Return, Extension, Amendment Deadlines

Select respective State Tax Return Deadlines.

2023, 2025, etc.

IRS Federal Income Tax Return, Amendment, Extension Deadlines

2023, 2025 Tax Year Income Tax Return Deadlines.

April 15, 2025

2021 Delaware Income Tax Return Refund

The last day to file and claim your 2021 Delaware Income Tax Return. This deadline does not apply if you owe Income Taxes.After that date your 2021 tax refund will expire. See details on unclaimed refunds.

April 15, 2026

2022 Delaware Income Tax Return Refund

The last day to file and claim your 2022 Delaware Income Tax Return. This deadline does not apply if you owe Income Taxes. After that date your 2022 tax refund will expire. See details on unclaimed refunds.

April 15, 2027

2023 Delaware Income Tax Return Refund

The last day to file and claim your 2023 Delaware Income Tax Return. This deadline does not apply if you owe Income Taxes. After that date your 2023 tax refund will expire. See details on unclaimed refunds.

April 15, 2028

2023 Delaware Income Tax Return Refund

TurboTax^® is a registered trademark of Intuit, Inc.
H&R Block^® is a registered trademark of HRB Innovations, Inc.