Do payments from Upwork or Stripe count as taxable income in Turkey?

Yes. Regardless of the platform, income earned by a Turkey-based person or company from foreign clients is subject to Turkish income or corporate tax. However, under Article 89/13 of the Income Tax Law, sole traders and self-employed individuals can deduct 100% of the earnings from foreign services from their taxable base — the rate rose from 80% to 100% by Presidential Decree No. 11257, applicable to periods beginning on or after 1 January 2026 — provided the payment arrives in Turkey as foreign currency by the filing date.