Abstract: U.S. military veterans are at a greater risk of suicide than non-veteran adults, and this risk is exacerbated in women veterans who have experienced military sexual trauma (MST). The Three-Step Theory (3ST) is an evidence-based model which describes the transition from suicidal ideation (SI) into action. It suggests that SI arises when physical and/or psychological pain is paired with hopelessness; SI increases when the pain and hopelessness outweigh feelings of connectedness. Informed by the 3ST, this paper examines PTSD, hopelessness, disconnection, and SI in 220 women veterans with MST who completed baseline assessments for a randomized clinical trial comparing Skills Training in Affective and Interpersonal Regulation (STAIR) to Present-Centered Therapy (PCT). In partial support of the 3ST, we found that higher PTSD severity was related to higher SI when veterans reported high hopelessness. However, we did not find that interpersonal problems exacerbated this interaction. Instead, we found that higher interpersonal problems were related to higher SI when patients reported high hopelessness. Findings highlight the importance of instilling hope, in addition to improving PTSD symptoms and interpersonal relationships, in reducing suicide risk.