Mariann Fischer Boel () (born 15 April 1943, Åsum) is a Danish politician, currently serving as European Commissioner for Agriculture and Rural Development. A member of the party Venstre, she had previously been minister of agriculture and foods since 2002, in the government of Anders Fogh Rasmussen.

As the Danish agriculture minister, she argued that it would be better if agricultural subsidies were entirely removed, a view that in many European countries is highly controversial.

Together with her husband, she owns three farms in Denmark. For some observers, this has called into question her neutrality in discharging her duties as a European Commissioner, as, for example, she would have the power to determine the purchasing price of different crops, thereby affecting her own personal income. She argues that it is her husband who runs the farms, and as she is not personally engaged in them, she is able to maintain neutrality.