Detection of underreporting in suicide risk assessment remains a significant concern in clinical practice. The aim of this research is to examine whether underreporting based on elevated Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) K-r and L-r scale scores may aid in identifying patients with suppressed scores on the Suicide/Death Ideation scale (SUI) and extra-test measures of suicide risk. We anticipated that, in voluntarily admitted psychiatric inpatients (N = 1,011) and individuals receiving outpatient services in a university-affiliated psychology clinic (N = 521), those indicated as underreporting would produce lower mean scores across SUI and extra-test measures of suicide risk, and that the magnitudes of the associations between SUI and extra-test scores would be strongest for those underreporting. A series of t tests and correlational analyses were conducted in both samples. Although those classified as underreporting consistently produced lower mean scores for SUI and extra-test measures of suicide risk, the magnitudes of the associations were consistently significant and stronger only in outpatients without K-r or L-r scale elevations. Clinical implications for this research include examining K-r elevations when assessing suicide risk and incorporating a therapeutic assessment approach to suicide risk assessment. (PsycInfo Database Record (c) 2021 APA, all rights reserved).