St. Johannis, Romanesque church in Wernigerode, Germany.

St. Johannis is an evangelical parish church on the northwestern edge of Wernigerode's historic Neustadt. Its Romanesque core survives in the west tower and south transept; the nave was rebuilt in the 15th century as a three-aisled hall church completed in 1497. Inside, a five-panel winged altarpiece dated 1415 on its reverse stands above the white altar, and an octagonal font of 1569 bears a portrait of Martin Luther.

The church was completed in 1279, when Bishop Volrad of Halberstadt consecrated the altar; the west tower and south transept survive from this Romanesque phase. In the 15th century the nave was rebuilt as a three-aisled hall church, finished in 1497. A restoration from 1864/65 to 1885 removed the Baroque galleries and seating and added furnishings by the local woodcarver Gustav Kuntzsch. Bombing on 22 February 1944 damaged the roof, choir and windows; the bricked-up west portal was reopened from 1970 and the tower ground floor linked to the interior in 1992.

The church is still the parish church of the Evangelical congregation, whose sign on the pulpit reads "ev. Kirchengemeinde". The five-panel winged altar of 1415 is opened according to the liturgical calendar: the weekday side shows the Annunciation and the Adoration of the Magi, the Sunday side four scenes of Mary's life, and the fully opened feast side Mary as Queen of Heaven among four musician angels.

The church stands at the northwestern edge of the historic Neustadt, a short walk from Wernigerode's town centre. The ground floor of the west tower was only linked to the nave in 1992, so enter through the main portal rather than the tower. The building is a heritage monument in Saxony-Anhalt and is used by the Protestant congregation, so visits may be limited during services.

The organ is the only surviving one of three Ladegast organs once in Wernigerode; its neo-Gothic case was designed by Carl Frühling and carved by Gustav Kuntzsch. The ten choir windows were redesigned in 2016 by Günter Grohs and made by the F. Schneemelcher glassworks in Quedlinburg.