Harshad Shantilal Mehta (29 July 1954 – 31 December 2001) was an Indian stockbroker and convicted fraudster. Mehta's involvement in the 1992 Indian securities scam (about ₹30,000 crore (equivalent to ₹2.3 trillion or US$27 billion in 2023)) led him to gain infamy for market manipulation.

Of the 27 criminal charges brought against Mehta, he was only convicted of four, before his death (by sudden heart attack) at age 47 in 2001. It was alleged that Mehta engaged in a massive stock manipulation scheme financed by worthless bank receipts, which his firm brokered for "ready forward" transactions between banks. Mehta was convicted by the Bombay High Court and the Supreme Court of India for his part in a financial scandal valued at ₹100 billion (US$1.2 billion) which took place on the Bombay Stock Exchange (BSE). The scandal exposed the loopholes in the Indian banking system and the Bombay Stock Exchange (BSE) transaction system, and consequently the Securities and Exchange Board of India introduced new rules to address those loopholes. He was on trial for 9 years, until he died at the end of 2001 from a heart attack.

Harshad Shantilal Mehta was born on 29 July 1954, at Paneli Moti, Rajkot district, in a Gujarati Jain family. His early childhood was spent in Borivali, where his father was a small-time textile businessman.

He did his early study in Janta Public School, Camp 2 Bhilai. A cricket enthusiast, Mehta did not show any special promise in school and came to Mumbai after his schooling for studies and to find work. Mehta completed his B.Com in 1976 from Lala Lajpatrai College, Bombay and worked a number of odd jobs for the next eight years.

In his early life, Mehta did jobs often related to sales, including selling hosiery, cement, and sorting diamonds. Mehta started his career as a salesperson in the Mumbai office of New India Assurance Company Limited (NIACL). During this time he became interested in the stock market and after a few days, resigned and joined a brokerage firm. In the early 1980s, he moved to a lower-level clerical job at the brokerage firm Harjivandas Nemidas Securities where he worked a jobber for the broker Prasann Pranjivandas Broker who he considered his "Guru".

Over a period of ten years, beginning 1980, he served in positions of increasing responsibility at a series of brokerage firms. By 1990, he had risen to a position of prominence in the Indian securities industry, with the media (including popular magazines such as Business Today) touting him as "Amitabh Bachchan of the Stock market".

Mehta founded Grow More Research and Asset Management, with the financial assistance of associates, when the BSE auctioned a broker's card and actively started to trade in 1986. By early 1990, a number of eminent people began to invest in his firm and utilize his services. It was at this time that he began trading heavily in the shares of Associated Cement Company (ACC). The price of shares in the cement company eventually rose from ₹200 to nearly ₹9,000 due to a massive spate of buying from a set of brokers including Mehta. Mehta justified this excessive trading in ACC shares by stating that the stock had been undervalued, and that the market had simply corrected when it revalued the company at a price equivalent to the cost of building a similar enterprise; the so-called "replacement cost theory" that he had put forward.

During this period, especially in 1990–1991, the media portrayed a heightened deified image of Mehta, calling him "The Big Bull". He was covered in a cover page article of a number of publications including the popular economic magazine Business Today, in an article titled "Raging Bull". His flashy lifestyle of a sea-facing 15,000 square feet penthouse in the tony area of Worli, complete with a mini golf course and swimming pool, and his fleet of cars including a Toyota Corolla, Lexus LS400, and Toyota Sera were flashed in publications. These further exemplified his image at a time when these were rarities even for the rich people of India.