We conducted 4 studies to develop and cross-validate scores on a multidimensional self-report measure of suicide and anger expression, the Suicide Anger Expression Inventory-28 (SAEI-28). The SAEI-28 evaluates Suicide Rumination, Maladaptive Expression, Reactive Distress, and Adaptive Expression with 7 content specific items each. Participants were between ages 14 and 47 years old. Study 1 developed a pool of content relevant and representative items for the new inventory. Study 2 explored potential domains of the SAEI-28 items, evaluating preliminary estimates of internal consistency reliability. Study 3 examined specific structures of the SAEI-28 items and scale reliability. Study 4 evaluated the fit of the oblique 4-factor model to 2 alternative solutions. Support was found for estimates of internal consistency reliability for the scales. Criterion-related validity and potential correlates for the SAEI-28 scales were also assessed.