IRS Tax Deadlines for 2026: The 2026 tax season officially kicks off in late January 2026, when the IRS begins processing 2025 returns. Most American taxpayers must file by the federal deadline of Wednesday, April 15, 2026. This year is unique due to new laws like the "One Big Beautiful Bill" Act, which introduces tax-free tips and overtime. Preparing early with direct deposit ensures faster refunds within 21 days.