| 1040/1040-NR | 4/18/2023 |
| 1040/1040-NR on Extension | 10/16/2023 |
| 1120 | 4/18/2023 (or the 15th day of the 4th month after the end of the fiscal tax year) |
| 1120 on Extension | 10/16/2023 (or the 15th day of the 10th month after the end of the fiscal tax year) |
| 1065/1120-S | 03/15/2023 (or the 15th day of the 3rd month after the end of the fiscal tax year) |
| 1065/1120-S on Extension | 09/15/2023 (or the 15th day of the 9th month after the end of the fiscal tax year) |
| 1041 | 4/18/2023 (or the 15th day of the 4th month after the end of the fiscal tax year) |
| 1041 on Extension | 10/2/2023 or 10/16/2023 for bankruptcy estate |
| 990 / 990-EZ / 990-N | 5/15/2023 (or the 15th day of the 5th month after the end of the fiscal tax year) |
| Organization dissolved, terminated, or liquidated: 5-1/2 months after the last day | |
| 990 or 990-EZ on Extension | 11/15/2023 (or the 15th day of the 11th month after the end of the fiscal tax year) |
| 990-T | 990 filers: 5/15/2023 (or the 15th day of the 5th month after the end of the fiscal tax year) |
| 990-T on Extension | 990 filers: 11/15/2023 (or the 15th day of the 11th month after the end of the fiscal tax year) |
| 706 | 9 months after the decedent's death |
| 706 on Extension | 6 months after the original due date |
| 709 | 4/18/2023 (for gifts made in 2022) |
| 709 on Extension | 10/16/2023 |