Seyyed Mostafa Tajzadeh (سید مصطفی تاج‌زاده‌; born 1956) is an Iranian progressive, reformist politician, and a member of Islamic Iran Participation Front. He is currently an Adviser to the President of Iran, since November 21, 2004.

Tajzadeh served as the Political Vice Minister of the Ministry of Interior of Iran in the government of Mohammad Khatami, and under the Minister Abdollah Noori, since 1997, after being introduced to Noori by Gholamhossein Karbaschi and Mohammad Atrianfar . The first Iranian elections for the city and village councils happened under Tajzadeh.

He started working in the Islamic Republic government as an employee of the Ministry of Culture and Islamic Guidance in May, 1982. He went up to became a vice minister when Mohammad Khatami was the Minister of Culture and Islamic Guidance, but after Khatami resigned from the post, he was downgraded to an assistant librarian. He left the ministry after a while, and worked for the newspaper Hamshahri until 1997.

Tajzadeh has a Ph.D. in political science from University of Tehran and has two daughters. His wife is Fakhrossadat Mohtashami, the daughter of a cleric, Ali Akbar Mohtashami, who is famous for his radical views against the Israel and the US. He has also lived in the United States for 31 months.