The Indian Institute of Technology (Banaras Hindu University) Varanasi (IIT-BHU) is a public technical university located in Varanasi, Uttar Pradesh, India. IIT (BHU) Founded in 1919 as the Banaras Engineering College, it became the Institute of Technology, Banaras Hindu University in 1968. It was later designated an Indian Institute of Technology in 2012. IIT (BHU) Varanasi has 16 departments, 3 inter-disciplinary schools and a Humanities & Social Sciences Section. It is located inside the Banaras Hindu University Campus.

IIT (BHU) Varanasi has formerly been known as the Banaras Engineering College (BENCO), the College of Mining and Metallurgy (MINMET), the College of Technology (TECHNO) and the Institute of Technology, Banaras Hindu University (IT-BHU). Its establishment is intimately linked with that of the Banaras Hindu University (BHU). The first convocation ceremony at BHU was held on 2 December 1920. BHU has the credit of first starting degree classes in Mechanical Engineering, Electrical Engineering, Metallurgical Engineering, Mining Engineering and Pharmaceutics, thanks to the foresight of its founder, Pt. Madan Mohan Malaviya.

The Department of Geology was started under BENCO in 1920. The Geology Department introduced courses in Mining and Metallurgy. The Department of Industrial Chemistry was started in July 1921. In 1923, Mining and Metallurgy were established as separate departments and in 1944, they were raised to the status of a college forming the College of Mining and Metallurgy (MINMET).

In 1968, BENCO, TECHNO and MINMET were merged and the Institute of Technology (IT-BHU) was established integrating the departments of Mechanical Engineering, Electrical Engineering, Civil and Municipal Engineering, Mining Engineering, Metallurgical Engineering, Chemical Engineering and Technology, Silicate Technology and Pharmaceutics. The Department of Silicate Technology subsequently became the Department of Ceramic Engineering. A Department of Electronics Engineering was also established. The departments of Applied Physics, Applied Mathematics and Applied Chemistry were established in 1985.

The earlier system of regional admission based on merit lists was replaced in 1972 by admission through Indian Institute of Technology Joint Entrance Examination (IIT-JEE) for undergraduate courses and Graduate Aptitude Test in Engineering (GATE) for postgraduate courses. In the tenth meeting of the IIT Council in 1972, it was also proposed to convert the then IT-BHU into an IIT and a committee was appointed by the IIT Council for the purpose but because of political reasons, the desired conversion could not be achieved then.

In 2003, Committees constituted by MHRD (Professors Joshi and Anand Krishnan Committees) had recommended for the conversion of the Institute into an Indian Institute of Technology (IIT). On 17 July 2008, the government of India issued a press release granting "In principle approval for taking over the Institute of Technology, Banaras Hindu University – a constituent unit of the Banaras Hindu University, a Central University, its conversion into an Indian Institute of Technology and integrating it with the IIT system in the country." The BHU Executive Council approved the proposal of the HRD ministry to convert IT-BHU to IIT (BHU) Varanasi, retaining academic and administrative ties to BHU.

On 4 August 2010 a bill seeking to amend the Institutes of Technology Act 1961 to declare IT-BHU an IIT was introduced in the Lok Sabha by Minister of State for HRD, D. Purandeswari. The Lok Sabha passed The Institutes of Technology (Amendment) Act, 2011 on 24 March 2011 and the Rajya Sabha on 30 April 2012, thereby formalizing the IIT status of the institute. The Bill was signed by the President of India on 20 June 2012 and notified in the gazette on 21 June. The Department of Architecture, Planning and Design was set up in the Institute in collaboration with IIT Roorkee, beginning its academic activities in the session 2019–2020. The first cohort of students consisted of 20 students admitted into the five-year programme through the JEE Advanced exam.

The institute celebrated its centenary year in 2019–2020. It organized a global alumni meet and other cultural events during the celebration. The 80-year-old BENCO chimney was also re-erected to commemorate the institute's completion of a century.