Sayyid Shahabeddin Hosseini Tonekaboni (Persian: سیّد شهاب‌الدین حسینی تنکابنی; born 3 February 1974), known professionally as Shahab Hosseini, is an Iranian actor and producer. he was nominated for the Crystal Simorgh for Best Supporting Actor at the Fajr Film Festival for his performances in A Candle in the Wind (2003) and Redemption at 8:20 (2004). In 2008, Hosseini won the Crystal Simorgh for Best Actor at the Fajr Film Festival for his role in Superstar.

Hosseini, along with the ensemble cast of A Separation, received the Silver Bear for Best Actor at the 61st Berlin International Film Festival in 2011. At the 2016 Cannes Film Festival, he won the Best Actor Award for his performance in The Salesman, becoming the first Iranian actor and the only Iranian male actor to receive this accolade. In 2019, the French government awarded him the Legion of Honour.

Seyyed Shahabedin Hosseini Tonekaboni was born on 3 February 1974, in Tehran, Iran. He is the eldest child in his family, with one brother and two sisters. His family originates from Tonekabon, Mazandaran Province. During his childhood, Hosseini lived for several years in Khorramabad with his family. He studied psychology at the University of Tehran but left the program to pursue emigration to Canada. Hosseini began his artistic career with student theater and later worked as a radio presenter.

In 1995, Hosseini married Parichehr Ghanbari. Their first son, Seyyed Mohammadamin, was born in the winter of 2003, and their second son, Seyyed Amirali, was born in the summer of 2011. In 2019, Hosseini married Sanaz Arjmand, a photographer and cinematographer.

Shahab Hosseini earned his high school diploma in Biology. He dropped out of the University of Tehran as a psychology student and emigrated to Canada. Later, he became a radio host in Iran and hosted a TV show for youth. He also took on some small acting roles in a few TV series. Hosseini's cinematic debut was in Rokhsareh (2002) directed by Amir Ghavidel. His career took off with his performance in the movie The Fifth Reaction directed by Tahmineh Milani. In June 2011, he announced that he would be taking a break but would return to cinema in 2013.

Shahab Hosseini's career began with radio presenting, and in 1998, he transitioned to television hosting in Iran. He appeared as a presenter on the program Oxygen. Hosseini also hosted several other programs, including Barpa Barpa, Morning Color, and Light and Shadow. On radio, he contributed as a presenter for programs such as Two Halves of an Apple, Our Voice, and Joyful Melody. In 2015, he served as a narrator for a pre-dawn television program.

In 2020, Hosseini hosted the talk show Hamrafigh on the Iranian streaming platform Namava, with the first episode airing on December 10, 2020.

Hosseini debuted as an actor in 2000 with the television series After the Rain. In 2001, he starred in Young Police, followed by Cold Fever in 2003. In 2006, he played Habib Parsa in Zero Degree Turn, directed by Hassan Fathi, a co-production between Iran, Hungary, France, and Lebanon. This role marked a high point in his television career.