| 01 May 2026, Fri | Goods and Services Tax | - | Taxpayers with Turnover below Rs 5 Crores to opt in or opt out of QRMP Scheme for Jul-Sep quarter till 31st July | 0 | Critical |
| 07 May 2026, Thu | FEMA | ECB-2 | Return of External Commercial Borrowings for April | 6 | Upcoming |
| 07 May 2026, Thu | Income Tax | Challan No. ITNS-281 | Payment of TDS/TCS of April including govt same-day rule & sections 392/393/394 | 6 | Upcoming |
| 07 May 2026, Thu | Income Tax | Form 127 (replaces 27C) | Upload declarations for non-deduction of TCS received in April | 6 | Upcoming |
| 10 May 2026, Sun | Goods and Services Tax | GSTR-7 | Monthly return by tax deductors | 9 | Upcoming |
| 10 May 2026, Sun | Goods and Services Tax | GSTR-8 | Monthly return by e-commerce operators | 9 | Upcoming |
| 11 May 2026, Mon | Goods and Services Tax | GSTR-1 | Outward supply return | 10 | Upcoming |
| 13 May 2026 | GST | IFF | Optional B2B invoice upload under QRMP | 12 | Upcoming |
| 13 May 2026 | GST | GSTR-5 | Return for non-resident taxable person | 12 | Upcoming |
| 13 May 2026 | GST | GSTR-6 | Return of Input Service Distributor | 12 | Upcoming |
| 15 May 2026 | PF | ECR | PF payment | 14 | Upcoming |
| 15 May 2026 | ESI | ESI Challan | ESI payment | 14 | Upcoming |
| 15 May 2026 | Income Tax | Form 16B | TDS certificate u/s 194-IA | 14 | Upcoming |
| 15 May 2026 | Income Tax | Form 16C | TDS certificate for rent above ₹50,000 u/s 194-IB | 14 | Upcoming |
| 15 May 2026 | Income Tax | Form 16D | TDS certificate u/s 194M | 14 | Upcoming |
| 15 May 2026 | Income Tax | Form 16E | TDS certificate on VDA u/s 194S | 14 | Upcoming |
| 15 May 2026 | Income Tax | Form 137 | Govt TDS/TCS book entry details | 14 | Upcoming |
| 15 May 2026 | Income Tax | Form 27EQ | Quarterly TCS return | 14 | Upcoming |
| 20 May 2026 | GST | GSTR-5A | OIDAR return | 19 | Normal |
| 20 May 2026 | GST | GSTR-1A | Amend GSTR-1 | 19 | Normal |
| 20 May 2026 | GST | GSTR-3B | Monthly GST payment return | 19 | Normal |
| 25 May 2026 | GST | PMT-06 | QRMP tax payment | 24 | Normal |
| 28 May 2026 | GST | GSTR-11 | UIN return | 27 | Normal |
| 30 May 2026 | GST | ITC-03 | ITC reversal for composition scheme | 29 | Normal |
| 30 May 2026 | Income Tax | Form 49C | Non-resident liaison office statement | 29 | Normal |
| 30 May 2026 | Income Tax | Form 141 | TDS deposit multiple sections | 29 | Normal |
| 30 May 2026 | Income Tax | Form 27D | TCS certificate issue | 29 | Normal |
| 30 May 2026 | Companies Act | PAS-6 | Share capital reconciliation | 29 | Normal |
| 30 May 2026 | Companies Act | FC-4 | Foreign company annual return | 29 | Normal |
| 30 May 2026 | LLP Act | LLP-11 | LLP annual return | 29 | Normal |
| 31 May 2026 | FSSAI | Form D1 | Annual return filing | 30 | Normal |
| 31 May 2026 | Income Tax | Form 108 | Trust option to defer income | 30 | Normal |
| 31 May 2026 | Income Tax | Form 109 | Income accumulation statement | 30 | Normal |
| 31 May 2026 | Income Tax | Form 113 | Donation reporting | 30 | Normal |
| 31 May 2026 | Income Tax | Form 114 | Donation certificate | 30 | Normal |
| 31 May 2026 | Income Tax | 24Q/26Q/27Q | Quarterly TDS returns | 30 | Normal |
| 31 May 2026 | Income Tax | 26QF | VDA quarterly statement | 30 | Normal |
| 31 May 2026 | Income Tax | 61A | SFT filing | 30 | Normal |
| 31 May 2026 | Income Tax | 61B | Reportable accounts | 30 | Normal |
| 31 May 2026 | Income Tax | Form 93 | PAN allotment (financial transactions & key persons) | 30 | Normal |