The importance of the fishing industry to Iceland's economy and the perception that EU membership (and its Common Fisheries Policy) will have an adverse effect on the fishing industry.
The perception that EU membership will have an adverse effect on Iceland's agricultural sector.
Iceland's strong ties with the United States, which included significant economic, diplomatic and military assistance, decreased Iceland's dependence on European countries.
The victories in the Cod Wars may have strengthened Icelandic nationalism and boosted the perception that Iceland can succeed through unilateral or bilateral means rather than compromise in multilateral frameworks.
The Icelandic electoral system favors rural areas, which are more eurosceptic.
The tendency for Icelandic elites to pursue education in the United States or eurosceptic European countries (such as the United Kingdom or the Nordic countries), and to cooperate more closely with political elites from those countries.
Icelandic nationalism and the legacy of Iceland's past as a colonial entity.
The impact of the Icesave dispute with the Netherlands and the UK.