Erich-Ollenhauer-Haus, Former Social Democratic Party headquarters in Gronau district, Bonn, Germany.

The Erich-Ollenhauer-Haus is an office complex with a concrete facade in Bonn's Gronau district that features a comb-shaped layout with four parallel wings. The structure faces Ollenhauerstraße and now houses various businesses and institutions.

The structure served as the German Social Democratic Party headquarters from 1975 to 1999, replacing earlier temporary facilities. After the party's relocation, various businesses and offices were established in its spaces.

The nickname "Baracke" (barracks) stuck to the SPD headquarters even after the 1975 new building opened, a reminder of the party's earlier 86-room temporary structure on the same site. The building is a stop on the Weg der Demokratie history trail through Bonn's former government quarter, and its address at Friedrich-Ebert-Allee corner Ollenhauerstraße honours two postwar party leaders.

The structure is now accessible for businesses and institutions and is located in a convenient position near central Bonn. Visitors can view the exterior facade and overall design from the street.

The brown anodized metal facade and continuous vertical glass windows create a repeating pattern along the street front. This design was a bold expression of technical modernism in 1970s German office architecture.