National immunization advisory committees are charged with making recommendations to either a governmental agency or the public regarding which vaccines that children and/or adults at specific ages, or with specific risk factors, should receive. However, there may be significant variability in a variety of aspects of such committees including the manner in which they are constituted, the process of their deliberations, and their authority. We explored the policies and roles of immunization advisory committees in each of 10 of the largest nations in Western Europe and found significant variation among the nations. Conceptually, this variation was able to be categorized into 6 specific domains; committee membership, processes of meetings, basis for decision making, financial issues, authority, and the role of manufacturers and insurers.