Background <p>Suicide attempts are a major global health concern, and more effective interventions are needed. This study aims to compare the effectiveness of the Attempted Suicide Short Intervention Program (ASSIP) and Acceptance and Commitment Therapy (ACT) in reducing suicidal ideation and mental pain among suicide attempters.</p> Methods <p>This randomized controlled trial (RCT) will recruit 60 participants (20 in each group) who have attempted suicide and whose contact information has been obtained from the Mental Health Unit of Eslamshahr Health Network. Participants will be randomly assigned to three groups: one receiving ASSIP in addition to treatment as usual (TAU), one receiving ACT alongside TAU, and a control group receiving TAU only. Data will be collected using the Beck Scale for Suicide Ideation (BSSI) and the Orbach &amp; Mikulincer Mental Pain Scale (OMMP) at pre-test, post-test, and follow-up stages. Primary outcomes are suicidal ideation and mental pain. Data on self-harm behaviors and re-attempts will also be descriptively collected during follow-up.</p> Results <p>We hypothesize that both ASSIP and ACT will lead to greater improvements in suicidal ideation and mental pain compared to the control group. We will also compare the effectiveness of the two interventions.</p> Conclusions <p>This study will provide valuable insights into the comparative effectiveness of ASSIP and ACT interventions for suicide attempters. The results are expected to inform clinical practice and contribute to evidence-based suicide prevention strategies. Findings will be disseminated through scientific publications, regardless of whether outcomes are positive, negative, or neutral.</p> Trial registration <p>The trial was registered at ClinicalTrial.gov <i>NCT07132099</i> on 20 August 2025.</p>