A Checklist providing an outline of the main legal arguments for a plaintiff's counsel to consider when preparing the opposition to the employer's motion for summary judgment in a disability discrimination or failure to accommodate lawsuit under the Americans with Disabilities Act (ADA) or the Rehabilitation Act of 1973 (Rehab Act). It addresses the McDonnell Douglas burden-shifting analysis, the plaintiff's burden to demonstrate the ability to perform the essential functions of the job with or without reasonable accommodation, and tips for opposing the employer's arguments. This Checklist addresses federal law but is useful for cases that also include state law claims.