Individuals with substance use disorders (SUDs) are at high risk of suicidal behaviors, highlighting the need for an improved understanding of potentially influential factors. One such domain is self-efficacy to manage suicidal thoughts and impulses. Psychometric data about the Self-Efficacy to Avoid Suicidal Action (SEASA) Scale within a sample of adults seeking SUD treatment (N = 464) is provided. Exploratory factor analysis supported a single self-efficacy construct. Lower SEASA scores, or lower self-efficacy, were reported in those with more severe suicidal ideation and those with more suicide attempts, providing evidence for convergent validity. Implications of measuring self-efficacy in the context of suicide risk assessment are discussed.