The present study reports the multistage development and evaluation of a Spanish translation of the Interpersonal Needs Questionnaire (INQ). The INQ measures the constructs of thwarted belongingness and perceived burdensomeness, which the interpersonal theory of suicide proposes are proximal causes of suicidal desire. Participants were bilingual Hispanic college students in the United States (n = 56), heritage Spanish-speaking college students in the United States (n = 281), college students in Spain (n = 1,016), psychiatric inpatients in Mexico (n = 181), college students in Mexico (n = 239), and Spanish-speaking U.S. adults (n = 104). Results indicated that a 9-item 2-factor solution (INQ-S-9) provided good fit. Multiple group analyses were also consistent with measurement invariance across nationalities and clinical severity. Finally, both subscale scores demonstrated good internal consistency, test-retest reliability, convergent validity, and concurrent associations with scores on measures of suicide ideation. Cultural considerations and implications for use in clinical and research settings are discussed. (PsycINFO Database Record (c) 2018 APA, all rights reserved).