Roggenmühle Lehndorf, Industrial grain mill in Lehndorf district, Brunswick, Germany.

Roggenmühle Lehndorf is a former large industrial grain mill on Hannoversche Straße in the Lehndorf district of Brunswick, built from 1912 in several stages to plans by architect Otto Orlishausen for the Braunschweiger Roggenmühle AG. The red-brick complex, about 100 m long and up to 30 m high, is dominated by a square water tower with a pointed roof, built in 1934 to supply sprinkler pressure in case of fire.

The mill was founded in 1912 by an engineering company and played a role in modern grain processing for the region. Following severe bombing during World War II in 1944, the facility was later restored and resumed operations in 1948.

The mill's name refers to rye, the grain it ground, and to Lehndorf, the district it has marked since 1912; its water tower became the emblem of both mill and district. Today the converted brick buildings house hairdressers, doctors' practices, physiotherapy rooms and three restaurants, so the former production site is used for services and dining.

The site is located on Hannoversche Straße in the Lehndorf district and is easy to reach. Following renovation in 2011, the grounds now serve restaurants, offices, and medical practices, making it accessible to visitors.

The site experienced multiple fires throughout its history, including a major one in 2007, after which parts of the original milling machinery were sold to South Africa. This shipment of equipment overseas shows how valuable the old machines were considered in other regions.