This paper discusses the rationale for international comparisons in educational achievement, presents factors which affect the validity of such comparisons, and makes recommendations for the role of the National Assessment of Educational Progress (NAEP) with respect to international studies. International comparisons are of interest in policy formation, resource allocation, and school improvement programs. Four prerequisites to international assessment also weigh heavily in an individual, national testing program: (1) the scope of item content must be equitable for each of the countries involved; (2) comparisons across countries will be facilitated by the use of common scaling techniques; (3) sampling must be representative and aedquate; and (4) the appropriate language must be used in testing. NAEP can facilitate international comparisons by collaborating with existing efforts such as those of the International Association for the Evaluation of Educational Achievement (IEA). NAEP can provide technical assistance in data collection and statistical analysis. An official liaison between NAEP and IEA is recommended at the policy level. An annual cooperative working meeting is also recommended. (GDC)