Simplex Infrastructures Ltd. is an Indian construction company established in 1924. The company was the first in Asia to use cast–in–situ driven piles, and also built Asia's first ever reinforced cement concrete (RCC) framed structure.

The company's business is divided into 6 segments - Roads, Railways & Bridges, Buildings, Industry, Power & Transmission, Marine, Ground Engineering, and Urban Infra.

Simplex Concrete Piles (India) Ltd.

was incorporated as a British Company in India by United Kingdom–based H.P.

Lancaster on 19 December 1924.

Shortly after its founding, Simplex introduced cast–in–situ driven piles at Calcutta (now Kolkata), becoming the first company to use the technology in Asia. The company began building major steel plants in 1935. Simplex constructed the King George Docks in Bombay (now Mumbai) in 1940. Following India's independence in 1947, Madho Das Mundhra and his family assumed control of the company. Simplex made its foray into the civil and structural construction of industrial projects in 1952, and the housing and building segment in 1955. In 1958, the company designed and constructed the 17-storey National Tower at Calcutta, the first ever RCC framed structure in Asia. ^{[2] [3] [4] [-1]}

Simplex entered into the business of civil and structural construction of thermal power plants in 1960.

It entered the urban utilities segment in 1965, constructing an HIT water treatment plant at Howrah, and entered the marine construction business in 1965. Simplex opened its first overseas office in Sri Lanka in 1982. The company entered the roads, bridges and railways construction segment in the same year. Simplex began undertaking piling work in Abu Dhabi, United Arab Emirates in 1990. The company fabricated an indigenous technique for jointed pre–cast concrete piles up to 150 meters depth at Ernakulam, Kerala in 1991, and built a hotel in Tashkent, Uzbekistan in 1992. ^{[2] [3]}

Simplex held an initial public offering and went public in 1993. The company forayed into the nuclear segment with the construction of the Kudankulam Nuclear Power Plant in March 2002. In 2003, the company entered the hydro power plant construction segment, and opened offices in the Middle East. Simplex received ISO 9001:2000 certification in 2004. The company achieved an annual turnover of ₹1,000 crore (US$150 million) in 2005. The same year, the company was renamed Simplex Infrastructures Ltd. to better reflect its presence in diverse construction segments. Simplex secured a contract to construct an irrigation canal in Hyderabad in 2005. The company secured contracts for doubling of railway tracks on South–Central Railway line on the Guntakal–Raichur railway, as well as several piling and civil contracts in the Middle East in 2006. ^{[3] [4]}

In 2010, Simplex made its entry into the power transmission and distribution, and road build–operate–transfer segments. The company entered into Ethiopian, Bangladeshi and Saudi Arabia n markets in 2011, and made its foray into underground mining in 2011. ^{[2] [4]}