When is the corporate income tax return due in Turkey for 2026?

The corporate income tax return must be filed between the first and last day of the fourth month following the close of the accounting period. For companies on a calendar year, this falls between 1 and 30 April 2026, with payment due within the same window.

How do provisional tax periods work in Turkey in 2026?

Provisional tax is filed in quarterly periods: Jan-Mar (filed in May), Apr-Jun (Aug), Jul-Sep (Nov), Oct-Dec (Feb). The declaration is due by the evening of the 14th day of the second month following each period, with payment due by the 17th.

Is VAT filed monthly or quarterly in Turkey?

VAT is generally filed monthly, with the return due by the 28th of the following month. Only a limited group of taxpayers under the simplified regime can file quarterly. The Withholding and Social Security Premium Return is also filed by the 26th of the following month.

What pre-filing checks should be done before each return?

Seven days before the filing date: (1) account reconciliation, (2) BA-BS cross-check of customer and supplier forms, (3) bank movement match against the ledger, (4) e-invoice/e-archive entry-exit completeness, (5) depreciation schedule and period-end inventory approval.

2026 tax calendar: critical dates for SMEs

TL;DR — 60 seconds

SME tax calendar 2026 critical dates:

31 March — Provisional tax Q4 filing

15 April — Corporate income tax filing

26 April — VAT filing

30 June — YMM CIT attestation report (extended from 1 June by Circular YMM/2026-1)

31 July 2027 — 8th Asset Peace deadline

Each missed deadline triggers tax-loss penalty + assessment risk. Monthly bookkeeping + compliance automates the calendar; solo SMMM or in-house team without system support remains exposed.

First question: Who tracks your provisional tax periods? No answer = systemisation needed.

The tax calendar may seem to follow the same rhythm every year, but filing deadlines, provisional tax periods and electronic notification requirements introduce small but expensive differences each year. In this short guide, I summarized the dates that matter most to SMEs in 2026.

Corporate income tax

[Sample content goes here — corporate income tax filing dates, payment periods and electronic filing requirements.]

Provisional tax periods

[Annual distribution of provisional tax periods, declaration and payment dates.]

VAT and withholding

[Monthly and quarterly VAT declarations, withholding and SSI service declaration dates.]

This article is for general information purposes. For a calendar tailored to your business, please consult a CPA.

A practical recommendation

Booking a review meeting 7 days before each filing date dramatically reduces the cost of last-minute corrections. Even when the process is digital, the inconsistencies caught by human eyes are too valuable to be underestimated.

Tax for E-commerce Businesses: 5 Common Mistakes — Marketplace tax adds calendar complexity
Turkey Technopark 2026 — Law 4691 YMM attestation calendar + 3% fund
Service: Bookkeeping & Ledger — Monthly operation + calendar tracking
Service: Tax Advisory — Filings + compliance
Guide: SME Tax — SME cluster hub

TL;DR — 60 seconds

Corporate income tax

Provisional tax periods

VAT and withholding

A practical recommendation

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