Reza Pahlavi (রেজা পাহলভি) is the eldest son of Mohammad Reza Pahlavi and Farah Diba. Mohammad Reza Pahlavi was the last Shah of the 53-year old Pahlavi dynasty in Iran.

Reza Pahlavi was officially named Crown Prince of Iran in 1967 at the time of his father's coronation. He is the founder and leader of the National Council of Iran, an exiled opposition group, participates in the Iranian democracy movement, and is a prominent critic of Iran's Islamic Republic government.

Reza Pahlavi was born in Tehran as the eldest son of Mohammad Reza Pahlavi, the Shah of Iran and Farah Pahlavi, the Shahbanu of Iran. Pahlavi's siblings include his sister Princess Farahnaz Pahlavi (born 1963), brother Prince Ali Reza Pahlavi (1966–2011), and sister Princess Leila Pahlavi (1970–2001), as well as a half-sister, Princess Shahnaz Pahlavi (born 1940).

When he was born, the Shah pardoned 98 political prisoners, and the government declared a 20% reduction in income tax. He studied at the eponymous "Reza Pahlavi School", a private school located in the royal palace and restricted to the imperial family and court associates. He was trained as a pilot; his first solo flight was at the age of 11, and he obtained his license a year later. He was a supporter of Taj Abadan football club.

As a cadet of the Imperial Iranian Air Force, he was sent to the United States in August 1978 to continue his pilot training. He was one of 43 cadet pilots in the one-year pilot training program at the former Reese Air Force Base, TX, which included flying the Cessna T-37 Tweet and Northrop T-38 Talon. As a result of the Iranian Revolution, he left the base in March 1979, about four months earlier than planned.

Reza Pahlavi came to Cairo, Egypt, in March 1980 with his family. When his father Mohammad Reza Pahlavi was ill and in the last weeks of his life, media reported that some monarchist elements had advised the Shah to oust Reza in favor of his younger son Ali Reza (who was 13 at the time) and a regency council, suggesting that Reza's background, training and interest in public affairs were too limited to become his successor. The Shah was understood to have rejected the idea and abdicated himself in favor of one of his two sons. When the Shah died on 27 July 1980, Farah Pahlavi proclaimed herself as the regent, a title in pretense. On his 20th birthday on 31 October, Reza Pahlavi declared himself to be the new king of Iran, Reza Shah II, and the rightful successor to the throne of the Pahlavi dynasty. Immediately afterward a spokesman for the United States Department of State, John Trattner, disassociated the U.S. government from Reza Pahlavi by stating that his government did not intend to support him, assuring that they recognized the Iranian government.

According to a People article published in 1978, Pahlavi dated a "blond, blue-eyed Swedish model he met in Rome". The same publication also reported that he lived with his girlfriend in Lubbock, Texas. As of 1980, he had an Egyptian girlfriend who was a student of The American University in Cairo, reportedly "closely guarded" by bodyguards.

Pahlavi began a relationship with Yasmine Etemad-Amini in 1985. They married on June 12, 1986, in Greenwich, Connecticut; he was 25 and she was 17. The couple have three daughters: Noor (born 3 April 1992), Iman (born 12 September 1993), and Farah (born 17 January 2004). Due to male only succession, and because Pahlavi only has daughters, his heir is his first cousin Patrick Ali Pahlavi.

Pahlavi was a keen football player and spectator. He was a fan of the capital's football club Esteghlal, then known as Taj (lit. 'Crown'), and his support was even televised by the National Iranian Radio and Television. The club performed in annual rallies organized on his birthday, identifying the club with the Pahlavi regime.

In 1981, UPI reported that Pahlavi attended the elite Gueziro Club in Cairo to watch tennis and was occasionally seen in discotheques at hotels in the vicinity of the Nile.

When interviewed about religion, Pahlavi said, "That's a private matter, but if you must know, I am, of course, by education and conviction, a Shia Muslim. I am very much a man of faith." Iranian writer Reza Bayegan also notes that Crown Prince Reza is alleged "deeply attached" to his Muslim faith. He has performed the Hajj (pilgrimage) to Mecca.