Assimilation and multiculturalism are often contrasted as opposite interethnic ideologies about cultural integration. Here, we address models of assimilation and multiculturalism and how group identity influences attitudes toward immigrants. One overlooked issue concerns the dynamic processes involved in integration. It is proposed that cultural inertia, defined as the desire to avoid cultural change, or conversely, to continue change once it is already occurring, can account for a number of seemingly discrepant findings. In particular, cultural inertia predicts that majority groups should prefer assimilation type models, whereas minority groups should prefer multicultural models. Resistance to change is the mediating process. Cultural inertia is used as a model to understand discrepant attitudes toward assimilation and multiculturalism across different groups.