Evidence is information that exists in physical or digital form—such as written agreements and e-mail communications—as well as testimony from witnesses who have personal knowledge of facts relevant to a dispute. Evidence generally must be relevant to be admitted in court and considered by the factfinder (judge or jury) in resolving a lawsuit. And some forms of evidence, such as expert witness testimony, must be shown to be sufficiently reliable (as determined by the judge) to be admitted in evidence.

In Alabama, evidence is regulated by both state statutes and rules of court, specifically the Alabama Rules of Evidence. These rules dictate what is considered admissible evidence in a court of law. Evidence must be relevant, meaning it must have any tendency to make a fact more or less probable than it would be without the evidence and the fact must be of consequence in determining the action. Physical and digital evidence, such as written agreements and email communications, must be authenticated to be admissible. Testimony from witnesses is also considered evidence if the witnesses have personal knowledge of the facts relevant to the dispute. Expert witness testimony is subject to a reliability standard, which is assessed by the judge. The expert's testimony must be based on sufficient facts or data, be the product of reliable principles and methods, and the expert must have applied the principles and methods reliably to the facts of the case. The Alabama Rules of Evidence are consistent with the Federal Rules of Evidence in many respects, but there may be specific local nuances that an attorney would need to consider when presenting evidence in an Alabama court.