Elsa Guðbjörg Vilmundardóttir (27 November 1932 – 23 April 2008) was the first Icelandic woman to complete a degree in geology and was the country's first female geologist.
Elsa was born in the Vestmannaeyjar. Her parents were Vilmundur Guðmundsson, an engineer from Hafnarnes, Reyðarfjörður (1907–34) and Gudrun Björnsdóttir, a seamstress (1903–75). At the age of three, Vilmundardóttir moved with her parents from the islands to Siglufjörður; her father drowned shortly thereafter. She then moved in with her maternal grandparents and at the age of 12, she moved to her mother's home in Reykjavík.
Vilmundardóttir graduated from Menntaskólinn í Reykjavík in 1953. In 1958, she went to Sweden and enrolled at Stockholm University. She studied geology in 1958–63. During her university years, she did geological fieldwork in the summers on behalf of Electricity Department, mostly though geological research of the proposed Búrfellsvirkjun hydropower plant. Her interest quickly focused on the geology of Tungnáröræfa. After completing her studies in 1963, she returned home and began working at jobs at the Electricity Department, followed by the National Energy Authority (NEA) of Iceland, when it was formed in 1967, working there until she retired in 2004. In 1980, an agreement was made between the NEA and Landsvirkjun on uniform geological mapping and was the supervisor of the project. Vilmundardóttir's research also included mapping tuff and lava north of Vatnajökull, as well as pyroclastic flows associated with prehistoric Hekla eruptions. She wrote about scientific research and was the co-author of 100 Geosites in South-Iceland.