The psychometric properties of the Suicide Ideation and Behavior Assessment Tool (SIBAT) were evaluated in 130 participants with varying levels of suicidality. Inter- and intra-rater reliability were assessed for clinician-rated outcomes, including the revised Clinical Global Impressions (CGI) of severity of suicidality (CGI-SS-r). Concurrent validity of patient-reported modules with Patient-reported Outcomes Measurement Information System (PROMIS) depression scale and Sheehan-Suicidality Tracking Scale Clinically Meaningful Change Measure (S-STS CMCM), and concordance between Columbia Classification Algorithm of Suicide Assessment (C-CASA) mappings for SIBAT, S-STS CMCM and Columbia–Suicide Severity Rating Scale (C-SSRS) were assessed. 52/130 participants (mean [SD] age: 38.3 [17.77] years) consented for multiple interviews (C-CASA mappings: n=52; rater-reliability: n=25/52). SIBAT demonstrated good intra-rater reliability (weighted-kappa range:0.64-0.76; CGI-SS-r, 0.75) and adequate inter-rater reliability (ICC range:0.68-0.82; CGI-SS-r, 0.81). There were strong correlations between PROMIS depression scores and SIBAT Module 5 ratings (Spearman correlations, r=0.64-0.74) and moderate correlations (r=0.29-0.72) between S-STS CMCM and SIBAT Modules 2, 3 and 5 ratings. Moderate agreement was noted between SIBAT C-CASA mappings and corresponding mappings from S-STS CMCM (weighted kappa: 0.54) and C-SSRS (weighted kappa: 0.56). Thus, the SIBAT provided valid assessment of suicidal ideation and behavior that could be reliably rated and adequately mapped to the C-CASA.