Malingering is a controversial attribution in forensic and related disability assessments (FDRA). It is critical for the practitioner to proceed with a comprehensive, scientifically informed assessment that is unbiased, which includes selecting psychological testing instruments that have the best psychometric properties for the case at hand. Depending on the context, as well as the scope of practice of the assessor, these tests might include performance validity tests and symptom validity tests, which can be both embedded and freestanding. These tests indicate whether the evaluee test data are credible, or whether the results indicate invalid response set. The latter is one basis for attributing malingering, but the assessor needs to consult the whole file. In cases with only minor symptom exaggeration or functional minimization, the assessor might consider the symptoms and dysfunctionality as genuine at the core. The base rate of malingering is another contentious issue, and this chapter analyzes the different estimates of malingering-related attributions in FDRA. The required number of test failures in an administered battery is also contentious, and solutions are proposed.