Forensic mental health evaluations for capital sentencing – i.e., sentencing proceedings that could include the death penalty – are uniquely comprehensive and challenging for forensic evaluators. Generally, the statutes and referral questions that guide these capital sentencing evaluations direct the evaluator to explore and document mitigation. The United States Supreme Court has defined capital mitigation as ‘any aspect of a defendant’s character or record, or any of the circumstances of the offense that the defendant proffered as a basis for a sentence less than death’ ( Lockett v. Ohio, 1978, p. 604). Of course, psychologists may serve different roles in the context of capital sentencing proceedings, including evaluating expert, teaching expert, mitigation specialist, or consultant. But psychologists evaluating mitigation typically must gather broad and detailed information about the defendant using varied sources, including defendant interview, collateral records, and collateral interviews. The evaluator then must consider information from this comprehensive investigation in light of broad scientific research in order to identify potentially mitigating data or themes. Capital sentencing may also evoke other narrow, specialised questions for forensic evaluation such as those addressing violence risk, known as ‘future dangerousness’ in some capital statutes, or those addressing intellectual disability that would render a defendant ineligible for a death sentence ( Atkins v. Virginia, 2002). Because the U.S. Supreme Court has consistently emphasised ‘death is different’ – that is, capital sentencing requires additional rigour and safeguards – the forensic mental health evaluations at capital sentencing also require optimal expertise, rigour, and thoroughness.