Church St. Marien, Catholic church in Oberwinterthur, Switzerland.

St. Marien is a Roman Catholic parish church in the Oberwinterthur district of Winterthur, built in 1935–1936 to designs by Stuttgart architect Albert Otto Linder. The church, dedicated as a Maria-Hilf-Kirche, has an attached hall seating over 200 people and a sisters' apartment. It is the fourth-oldest Catholic church in the city.

The parish began as a daughter of St. Peter and Paul; from 1907 Mass was held in the Römerhof restaurant, whose hall became a chapel in 1919. After the Römerhof burned in 1925, the church was built in 1935–1936 by Stuttgart architect Albert Otto Linder, blessed on 3 May 1936 by Bishop Laurenz Matthias Vincenz and consecrated on 27 April 1957 by Bishop Christian Caminada. It became an independent parish in 1970.

The church was dedicated as a Maria-Hilf church, and the sisters of the Congregation of the Adorers of the Blood of Christ from Schaan in Liechtenstein lived in an attached convent, caring for the sick and elderly and working in other parish areas. The parish was raised to an independent parish in 1970, separated from St. Peter and Paul.

The church is accessible to visitors during worship services and offers clear views of its interior layout from the entrance. Note that parking is limited in the immediate area, and visiting outside of service times allows for quieter exploration.

The church bells were cast in 1957 by the Karl Czudnochowsky foundry and together weigh about 7.100 kilograms. They are tuned in harmony with the nearby Reformed Church bells, creating a distinctive sound over the neighborhood.