St. Mary's Cathedral, Sandakan, Catholic cathedral in Sandakan, Malaysia.

St. Mary's Cathedral in Sandakan is a large church with white walls, high ceilings, and stained glass windows that fill the interior with light. The main prayer space can hold a sizable number of worshippers, and there is a separate prayer grotto at the front dedicated to Our Lady of Lourdes.

The Mill Hill Fathers opened a mission and St. Mary's School on this hill in 1883; a permanent church followed in 1904. Japanese forces razed it in 1943. From 1952 Father Anthony Mulders rebuilt the church largely with mission and boarding-school labour, and Bishop James Buis consecrated it in 1961. It became a cathedral in 2007 with the creation of the Diocese of Sandakan.

The hill itself is named St. Mary's Hill, after the kajang hut that Fr. Alexander Prenger dedicated to the Virgin Mary in 1883. The Franciscan Missionaries of St. Joseph, known as the White Sisters, opened North Borneo's first convent here on 5 November 1891, with Sisters Theresa, Peter, Rose and Collete. A small chapel at the rear of the church was completed in late 1999.

The church stands on St. Mary's Hill, a short walk from Sandakan's town centre, with the Lourdes-style grotto built into the rock of a nearby hill in front of it and a small chapel at the rear, finished in late 1999. Visitors reach the site by road up the hill; the grounds are shared with St. Mary's School.

The building has long been connected to a local school that was among the first educational institutions established in the region. This link shows how the religious center played a role in the community's development from early on.