Objective: The Interpersonal Needs Questionnaire (INQ‐15) is a self‐report measure of thwarted belongingness and perceived burdensomeness, two constructs associated with suicidal ideation. The objective of the current study was to translate the INQ‐15 from English to Italian (INQ‐15‐I) and to test its factor structure, reliability, and validity in Italian samples. Method: We examined (a) whether the components of the hypothesized two‐factor measurement model are invariant across a community sample (N = 510) and a clinical sample (N = 259); (b) the relations between the INQ‐15‐I factors and measures of depression (Beck Depression Inventory‐II), hopelessness (Beck Hopelessness Scale), and suicidal ideation (Beck Scale for Suicide Ideation); (c) the reliability and psychometric properties of the INQ‐15‐I. Results: Results from multigroup confirmatory factor analyses supported the adequacy of the two‐factor model to represent thwarted belongingness and perceived burdensomeness. The model is invariant across community and clinical groups, showing excellent fit. The two INQ‐15‐I scales measure highly intercorrelated constructs. Both significantly correlate with depression, hopelessness, and suicidal ideation, and correlations are high in the clinical sample. Conclusion: The INQ‐15‐I is a valid and reliable measure of thwarted belongingness and perceived burdensomeness. Implications for research, assessment, and intervention in suicidal ideation are discussed.