This article was written to introduce readers to the bodies of work that inform experts who conduct evaluations of plaintiffs or offer generic testimony in cases involving claims of psychological injuries in the aftermath of sexual trauma, including childhood sexual abuse, adult sexual assault, and sexual harassment. In addition to summarizing the research literatures on those three areas of maltreatment, it reviews what mental health experts should know about our laws, about professional standards for evaluations, and about other relevant areas of research, such as assessment of posttraumatic stress symptoms, disclosures by young children, “normal” childhood sexual behaviors, “repressed” or “recovered” memories, memory and trauma, memory distortions, and resilience.