Toğrul (Tuğril, Tuğrul or Toghrïl Beg; c. 990–September 4, 1063) was the second ruler of the Seljuk dynasty. Tuğrul united the Turkomen warriors of the Great Eurasian Steppes into a confederacy of tribes, who traced their ancestry to a single ancestor named Seljuk, and led them in conquest of eastern Iran. He would later establish the Seljuk Sultanate after conquering Persia and retaking the Abbasid Capital of Baghdad from the Buyid Dynasty in 1055. Tuğrul relegated the Abbassid Caliphs to state figureheads and took command of the caliphate's armies in military offensives against the Byzantine Empire and the Fatimid Caliphate in an effort to expand his empire's borders and unite the Islamic world.

He ascended to power c. 1016. In 1025 he, his nephew Arslan, and his brother Chaghri (Çağrı) served under the Kara-Khanids of Bukhara, but they were defeated by the Ghaznavid Empire under Mahmud of Ghazni, and Toğrul was forced to flee to Khwarezm while Arslan settled in Khorasan. When their uncle was later driven out of Khorasan by Mahmud, Toğrul and his brother moved onto Khorasan and conquered the cities of Merv and Nishapur in 1028–1029. They then extended their raids to Bokhara and Balkh and in 1037 sacked Ghazni and in 1038 he was crowned Sultan at Nishapur. In 1040 they decisively won the Battle of Dandanaqan against Mahmud's son, Mas'ud I forcing Mas'ud I to abandon his western provinces and flee towards Lahore. Toğrul then installed Chagri to govern Khorasan and prevent a Ghaznavid reconquest, then moved on to the conquest of the Iranian plateau in 1040-1044. By 1054 his forces were contending in Anatolia with the Byzantines and in 1055 he was commissioned by the Abbassid Caliph Al-Qa'im (caliph) to recapture Baghdad from the Fatimids. A revolt by Turkmen forces under his foster brother Ibrahim Yinal, Buyid forces and an uprising against the Seljuks led to the loss of the city to the Fatimids Caliph in 1058. Two years later Toğrul crushed the rebellion, personally strangling Ibrahmin with his bowstring and entered Baghdad. He then married the daughter of the Abbasid Caliph.

He died childless in the city of Rayy in modern Iran and was succeeded by his nephew Suleiman which was contested by Alp Arslan, both of them sons of his brother Chagri Begh. His cousin Kutalmish who had both been a vital part of his campaigns and later a supporter of Yinal's rebellion also put forth a claim. Alp Arslan defeated Kutalmish for the throne and succeed on April 27th, 1064.