Marienborn is a village and a former municipality in the Börde district in Saxony-Anhalt, Germany. Since 1 January 2010, it has been part of the municipality of Sommersdorf. It is about southwest of Haldensleben. The historic pilgrimage centre near the former inner German border is known for the preserved Helmstedt-Marienborn border crossing, now a memorial site.
In 1191 Wichmann von Seeburg, then Archbishop of Magdeburg, established an asylum at the site of an apparition of the Virgin Mary and a spring (Born) with healing waters, which during the 13th century evolved into a monastery for Augustinian nuns. The sisters of Marienborn abbey left a monastery church and cloister with foundations from about 1200, while the pilgrimage chapel at the spring is a replica dating from the 19th century.