International tax competition has been significantly increased since 1980s as a result of liberalized financial and fiscal policies, while this leads sovereign nations faced budgetary deficit problems and public finance related considerations. This paper aims to analyze how Turkish tax system is affected by international tax competition, services submitted by tax havens and facilities used by multinationals. In 2006, a new Corporate Income Tax Law was introduced in Turkey. One of its purposes is to combat against harmful tax competition and therefore it covered defensive measures such as controlled foreign company (CFC), thin capitalization rule and transfer pricing regulation, to prevent companies from leaving their income abroad. This study aims to analyze effects of international tax competition in Turkey whether there are change in tax rates, tax structure, and tax revenue; and how the government respond it, as a beneficiary; or, a loser.