In order to enter Turkey you are kindly advised to have a passport valid at least 6 months from the date you arrive in Turkey.
Regarding the visa, there are 3 situations for entering in Turkey: no visa, e-visa needed or visa needed. For more information please check your country in one of the 3 below situations:
Free visa – no formalities needed
Free visa – depending on the nationality, free visa can be given from 30 up to 90 days.
Free visa allowed nationalities: Albania, Andorra, Argentina, Azerbaijan, Belarus, Belize, Bolivia, Bosnia-Herzegovina, Brazil, Brunei, Bulgaria, Chile, Colombia, Costa Rica, Czech Republic, Denmark, Ecuador, El Salvador, Estonia, Finland, France, Georgia, Germany, Greece, Guatemala, Guyana, Honduras, Hong Kong Special Administrative Region of PRC*, Hungary, Iceland, Iran, Israel, Italy, Japan, Jordan, Kazakhstan, Kosovo, Kuwait, Kyrgyzstan, Latvia, Lebanon, Liechtenstein, Lithuania, Luxemburg, Macao Special Administration, Macedonia, Malaysia, Moldova, Monaco, Mongolia, Montenegro, Morocco, New Zealand, Nicaragua, Panama, Paraguay, Peru, Qatar, Romania, Russian Federation, St. Christopher (St. Kitts) & Nevis, San Marino, Serbia, Seychelles, Singapore, Slovakia, Slovenia, South Korea, Sweden, Switzerland, Tajikistan, Thailand, Trinidad and Tobago, Tunisia, Turkish Republic of Northern Cyprus, Turkmenistan, Ukraine, Uruguay, Uzbekistan, Vatican, Venezuela.
*Hong Kong citizens who have “British National Overseas Passport” are subject to visa and they can obtain their three month period multiple entry e-Visas via the website www.evisa.gov.tr Holders of “Document of Identity for Visa Purposes-Hong Kong (D.I)” must get their visas from the Turkish diplomatic or consular missions abroad
E-visa needed in advance – please see all formalities needed here: www.evisa.gov.tr.
E-visa allowed nationalities: Antigua-Barbuda, Armenia, Australia, Austria, Bahamas, Bahrain, Barbados, Belgium, Greek Cypriot Administration, Indonesia, Ireland, Jamaica, Mexico, Namibia, Netherlands, Norway, Oman, Poland, Portugal, St Lucia, St Vincent and the Grenadines, Saudi Arabia, South Africa, Spain, Sri Lanka, Surinam, Taiwan, United Arab Emirates, United Kingdom**, Zambia.
**UK passports holders with “British National Overseas”, “British Subject” and “British Protected Person” nationality are subjected to visa and they can only get their visas from the Turkish diplomatic or consular missions abroad.
Visa needed in advance from the abroad consular or diplomatic missions of the Republic of Turkey. Some of the below nationalities can opt for e-visa in case of having a valid Schengen members or USA, UK, Ireland visa or residence permit. For more information please check the Republic of Turkey Ministry of Foreign website. http://www.mfa.gov.tr/visa-information-for-foreigners.en.mfa.
Visa needed nationalities: Afghanistan, Algeria, Angola, Bangladesh, Benin, Bhutan, Botswana, Burkina Faso, Burundi, Cambodia, Cameroon, Canada, Cape Verde, Central African Republic, Chad, Republic of China, Comoros, Cote d’Ivoire, Croatia, Cuba, Democratic Republic of Congo, Djibouti, Dominica, Dominican Republic, East Timor, Egypt, Equatorial Guinea, Eritrea, Ethiopia, Fiji, Gabon, Gambia, Ghana, Grenada, Guinea, Guinea-Bissau, Haiti, India, Iraq, Kenya, Kiribati, Laos, Lesotho, Liberia, Libya, Madagascar, Malawi, Maldives, Mali, Malta, Marshall Islands, Mauritania, Mauritius, Mozambique, Myanmar, Nauru, Nepal, Nigeria, North Korea, Northern Mariana Islands, Pakistan, Palau Republic, Palestine, Papua New Guinea, Philippines, Republic of Congo, Rwanda, Sao Tome and Principe, Senegal, Sierra Leone, Solomon Islands, Somalia, South Sudan, Sudan, Swaziland, Syria, Tanzania, Togo, Tonga, Tuvalu, Uganda, Uganda, United States of America, Vanuatu, Vietnam, Western Samoa, Yemen, Zimbabwe.