In this chapter, the authors present a multifaceted treatment of the persistent controversy over ethnic bias in ability tests. After introducing the controversy and the widely misunderstood concept of bias, we address objections to tests and testing raised by minority advocacy groups and explore the origins of such objections. We touch upon proposed sources of test bias, such as differential predictive validity and inequitable social consequences of testing. Next, we distinguish bias from similar concepts: unfairness, offensiveness, culture fairness, and culture loadedness. We also distinguish similar controversies, such as the etiology of putative ethnic differences. The crux of the test bias debate is intergroup score differences observed for over a century. Authors have proposed numerous explanations for these differences, primarily social inequalities, genetic potential, an interaction between the two, and test bias. Some authors have assumed a priori that any mean ethnic difference in ability scores must result from bias. We evaluate the merits of these approaches, particularly the latter, before reviewing the bias literature. Our review includes predictive, construct, and content bias and related issues such as situational bias. Results provide little evidence for substantial ethnic test bias. We conclude, in part, with recommendations for clinicians, researchers, and others.