St. Katharina, Roman Catholic church in Rehren, Germany.

St. Katharina is a Roman Catholic church on the southern edge of Rehren, built of light tan, regularly coursed stone blocks. A square tower with a red-edged pitched roof and a small cross rises on the left; its front face has two dark louvered openings with pale vertical pillars and, lower down, two narrow rectangular windows. The main body has a steeply pitched red-edged roof, and dark doors sit in a recessed entrance reached by a few steps. Inside, a gently curved wooden ceiling covers a nave with pews along a central aisle, and the Stations of the Cross hang on the east wall.

Catholics displaced from Central and Eastern Europe after 1945 settled in the Protestant Auetal in larger numbers, leading to the founding of a Catholic parish in Rehren in 1946; services were first held in secular rooms. The foundation stone of the church was laid in 1960 and the building was consecrated in 1961. It was designed by Hanover architect Wilhelm Fricke, who also led the postwar rebuilding of Hildesheim Cathedral.

The altar displays a sculpture showing the Lamb of God holding a victory flag, symbolizing Christ's resurrection. This imagery shapes the spiritual focus of the interior space.

The church is administered by the St. Marien parish in Bückeburg and sits near the A2 motorway. Visiting on foot from nearby Rehren is straightforward and takes only a few minutes from the town center.

The church was designed by Hanover architect Wilhelm Fricke (1890–1964), who also directed the postwar rebuilding of Hildesheim Cathedral and designed St. Michael's in Salzgitter-Lebenstedt. The street name Zur Obersburg recalls a country house built from 1912 that housed a gynaecological and maternity clinic from 1947 to 1983.