Gerdau is a Brazilian company, a leader in the production of long steels in Latin America and North America and one of the largest suppliers of special long steels. It has industrial operations in 14 countries - in Latin America, North America and Europe. It is the largest recycler in Latin America and transforms millions of tons of scrap into steel annually. With nearly 140 thousand shareholders, Gerdau is listed on the São Paulo, New York and Madrid stock exchanges.

In 2023 it had a steel production of 12.7 million tons.[1]​.

Gerdau was founded by João Gerdau. Son of Johannes Gerdau and Anna Focken, peasants residing in Neuenfelde, in the Kingdom of Hanover. Born in Altona, currently a neighborhood of Hamburg, in the then Kingdom of Prussia, João emigrated to the south of the Brazilian Empire, in 1869, in search of better living conditions and new ventures, landing in the Port of Rio Grande, province of São Pedro do Rio Grande do Sul, while still young. He settled in the Colonia de Santo Ângelo, a territory that currently belongs to Agudo, in the Brazilian state of Rio Grande do Sul. In the same city he initially invested in commerce. Later, in 1884, he founded a textile trading house in Cachoeira do Sul. In search of new opportunities, he moved with his wife Alvine Gerdau and their three children, Hugo, Walter and Bertha, to Porto Alegre, the state capital.

In Porto Alegre, he bought the Pontas de Paris nail factory in 1901, marking the origin of the group. Shortly before his death, on November 24, 1917, the business passed into the hands of his son, Hugo Gerdau. With the abundant production of cloves, Rio Grande do Sul was no longer dependent on imports. In 1933, the nail factory expanded its production with the construction of a new unit in Passo Fundo, in the interior of the state.

In 2005 it acquired the Spanish company Sidenor for €443 million,[2][3]​ and in May 2016 it sold the company again, for a third of what it paid for it, to its previous management team, which refounded it as Sidenor.[2]​.

On June 28, 2006, Gerdau acquired 52% of the shares of SIDERPERU.[4]​.

In Chile it operated from 1992, when it bought the local steel company Aza,[5]​ until April 2018, when it announced that it would sell its operations to a group of Chilean businessmen, consisting of three production plants with an installed capacity of 520,000 tons of recycled long steel per year and its distribution network in that country.[6]​.