Mental illness and disability affect millions of individuals yearly in the U.S. The most important legislation protecting the mentally disabled in the workplace in the U.S. over the last half century has been the Americans with Disabilities Act (ADA) and its associated legislation and guidance. Although the employee should first request reasonable accommodation with the employer, evaluation by a mental health professional is one of the initial steps for individuals who report significant psychiatric symptoms that are impairing their functioning at work in the U.S.. Important regulations and laws in the United States that are essential knowledge to performing thorough mental disability evaluations include the ADA and Americans with Disabilities Act Amendments Act of 2008 (ADAAA), Social Security Disability, Workers' Compensation, and private disability insurance. These laws differ in applicability and in their definitions of disability. Social Security Disability is applicable to workers who have long-term impairments regardless of whether the disability arose on or off the job, while Worker's Compensation is specific to persons with work-related illness and injuries that occur on the job (Reno, Williams, & Sengupta, ). The Social Security definition of a disabled person is a person who is not "able to engage in any substantial gainful activity because of a medically-determinable physical or mental impairment(s): that is expected to result in death, or that has lasted or is expected to last for a continuous period of at least 12 months" (Social Security Red Book, ). However, the Workers' Compensation definition of what illnesses/injuries are compensated, the level of benefits and who provides the insurance are state-specific. Due to these differences in definition of disability, it is essential for the mental health professional performing a mental disability evaluation to clarify with the referral source or referring agency which legislation and laws they feel are directly relevant to the specific situation before starting the evaluation. While the ADA and ADA Amendments Act of 2008 have had the greatest impact on the improvement of conditions for mentally disabled individuals in employment over the last 25 years, they have also been the most challenging by far for mental health experts to understand and apply (Cook, ). Interestingly, the ADA has had a much quicker effect on improving access to services for the medically disabled as compared with the mentally disabled in the U.S. (Ullman, Johnsen, Moss, & Burris, ). This article reviews the history and status of current ADA- and ADAAA-related law and employment as well as Canadian disability law and global progress towards universal disability legislation as evidenced by the 2006 Convention on the Rights of Persons with Disabilities. Copyright © 2017 John Wiley & Sons, Ltd.