Opinion testimony is a type of evidence given by a witness in a court of law. It is a form of testimony that is based on the witness’s opinion or point of view, rather than facts or direct knowledge. Opinion testimony can include both expert and lay opinion. Expert opinion testimony is given by an expert witness who has knowledge, experience, or special qualifications in a particular field, while lay opinion testimony is given by a non-expert witness, such as a witness to a crime. Both types of opinion testimony must be based on the facts known to the witness and must not include speculative or subjective opinions.