The paper provides an overview of our current knowledge of multiculturalism, which refers to the acceptance of and support for the plural nature of a society among mainstreamers and immigrant groups. Multiculturalism is found to be a multifaceted, unifactorial attitude with a good cross-cultural equivalence. Educational level tends to be positively related to multiculturalism at the individual level. Cross-national differences in multiculturalism are positively related to GNP, but unrelated to multiculturalism policies. Both a cross-sectional and a longitudinal study showed a remarkable stability of multiculturalism scores in the Netherlands in the last decade, despite the increasingly restrictive immigration laws and negative change in public discourse over the period. Implications of these findings are discussed.