Psychological closeness to preferred suicide methods has consistently been linked to increased suicidal ideation, intent, and behaviors in past research. However, past work was limited by single-item measures. This study presents the development and validation of a multidimensional self-report measure of psychological closeness to preferred suicide methods. Samples of students (n = 489) and community-based adults (n = 278) with current suicidal ideation and/or a lifetime suicide attempt completed a series of self-report measures, including an item pool for the Psychological Closeness to Suicide Methods Scale. The Psychological Closeness to Suicide Methods Scale item pool was reduced from a pool of 54 items to 15 items, across four subscales, that are highly discriminant and of varying levels of difficulty. Measurement invariance was established across suicide attempt history, gender, and race/ethnicity, and convergent, discriminant, and incremental validity were examined. Distinct facets of psychological closeness were uniquely related to current suicidal ideation versus suicide attempt histories. Overall, these findings suggest that the Psychological Closeness to Suicide Methods Scale is a reliable, valid, and incrementally useful measure of multiple dimensions of psychological closeness to suicide methods. Clinical implications, limitations, and future research directions are discussed. (PsycInfo Database Record (c) 2025 APA, all rights reserved).