Mar Dinkha IV (Classical Syriac: ܡܪܝ ܕܢܚܐ ܪܒܝܥܝܐ and Arabic: مار دنخا الرابع), born Dinkha Khanania (15 September 1935 – 26 March 2015) was an Eastern Christian prelate who served as the 120th Catholicos-Patriarch of the Assyrian Church of the East. He was born in the village of Darbandokeh (Derbendoki), Iraq, and led the Church in exile in Chicago for most of his life.

Dinkha Khanania was born in Iraq and baptized in the Church of Mar Qaryaqos located in the village of his birth, Darbandokeh. Khanania (also written as "Denkha Kh'nanya") gained his elementary education under the tutorship of his grandfather, Benyamin Soro. In 1947—at the age of eleven—he was entrusted to the care of Mar Yousip Khnanisho, Metropolitan and the Patriarchal representative for all Iraq, the second-highest-ranking ecclesiastic of the Assyrian Church of the East. After two years of study, he was ordained deacon in the church of Mar Youkhana in Harir by Mar Yousip on 12 September 1949. On 15 July 1957, he was ordained to the priesthood, and appointed to minister Urmia, Iran. He was the fourth in the line of succession to the Bishopric of Urmia.

Mar Dinkha's priesthood as Metropolitan of Iran and Tehran reestablished a line of succession which had ceased to exist after the 1915 assassination of his predecessor. In 1962, Mar Dinkha moved from northern Iraq to Tehran. During his tenure in Iran, he established a seminary and advocated for Assyrian nationalism and ecumenism. Responding to popular demand, Catholicos-Patriarch Shimun XXI Eshai consecrated Mar Dinkha as bishop on 11 February 1962, in the church of Martyr Mar Gewargis in Tehran.

Mar Dinkha died on 26 March 2015 in Rochester, Minnesota.

After the assassination of Mar Shimun XXI Eshai, the Church of the East had an urgent need to restore its leadership. In 1976, the prelates of the church convened in London to elect a new Catholicos Patriarch and chose Mar Dinkha as the most qualified candidate to fill the post. He was consecrated on 17 October 1976, in the West London Church of St. Barnabas, Ealing. With this consecration, Mar Dinkha IV became the successor to the Apostolic see of Seleucia-Ctesiphon (Babylon). He also announced that the hereditary line of succession for the Patriarchy which had existed for 500 years was discontinued with his tenure, allowing any cleric from the Church of the East to be elevated to Catholicos-Patriarch.

Dinkha established headquarters—along with four other houses of worship—in Chicago, Illinois, United States, in part due to the instability of the Iran–Iraq War. This conflict as well as Saddam Hussein's policy of Arabization in Iraq, the Gulf War and subsequent sanctions against Iraq intensified the Assyrian diaspora from the region. Meanwhile, the Islamic Revolution and Shia emphasis in Iran created a tense situation for Assyrians in the Middle East. During the reign of Shimun XXI and Dinkha IV, American membership in the Church of the East rose from 3,200 in the 1950s to approximately 100,000 in 2008.

In 2005, the Patriarch conducted discussions with President of Iraqi Kurdistan Masoud Barzani on returning to the Apostolic See in northern Iraq and constructing a new residence in Ankawa. On 15 July 2007, Mar Dinkha celebrated 50 years of his priesthood. A ceremony was held at St. George Cathedral in Chicago, where a portion of Ashland Avenue was renamed "His Holiness Mar Dinkha IV Blvd". In 2008, he received an honorary degree from the University of Chicago, in part because of his emphasis on education—he stated a goal of only appointing theologians with doctoral degrees to the position of bishop.

Dinkha made ecumenism a priority during his reign, as well as advocacy for the Assyrian people.