Localizing user interfaces has been proven beneficial for both user satisfaction and work efficiency; however, current localization methods disregard the many facets in the cultural background of today‘s typical user by simply adapting to a certain country. The chapter proposes a new approach to localization by modeling the user’s culture according to its understanding in cultural anthropology. Contrasting this view with cultural influences on user interface perception and preferences, the authors obtain an intersection of aspects that need to be included in a cultural user model, and deduce which user interface aspects have to be adaptable. With this, the chapter turns towards the application of their approach with the help of adaptive user interfaces, which allow the flexible composition of different user interface elements. The authors describe one possibility for implementing such culturally adaptive systems, and exemplify the design of different gradations of user interface aspects with the help of their MOCCA system.