Suicide rates in the United States rose 35.2% from 1999-2018. As emergency department (ED) providers often have limited training in management of suicidal patients and minimal access to mental health experts, clinical practice guidelines (CPGs) may improve care for these patients. However, clinical practice guidelines that do not adhere to quality standards for development may be harmful both to patients, if they promote practices based on flawed evidence, and to ED providers, if used in malpractice claims. In 2011, the Institute of Medicine created standards to determine the trustworthiness of CPGs. This review assessed the adherence of suicide prevention CPGs, intended for the ED, to these standards. Secondary objectives were to assess the association of adherence both with first author/organization specialty (ED vs non-ED) and with inclusion of recommendations on substance use, a potent risk factor for suicide. This is a systematic review of available suicide-prevention CPGs for the ED in both peer-reviewed and gray literature. This review followed the PRISMA standards for reporting systematic reviews. Of 22 included CPGs, the 7 ED-sponsored CPGs had higher adherence to quality standards (3.1 vs 2.4) and included the highest-rated CPG (ICAR2E) identified by this review. Regardless of specialty, nearly all CPGs included some mention of identifying or managing substance use. Most suicide prevention CPGs intended for the ED are written by non-ED first authors or organizations and have low adherence to quality standards. Future CPGs should be developed with more scientific rigor, include a multidisciplinary writing group, and be created by authors working in the practice environment to which the CPG applies.