BackgroundAmong people with bipolar disorders, there are high rates of impulsivity and suicide attempts. Efforts to reduce suicide are hindered by the lack of conclusive evidence on interventional programs for those at risk. Thus, this work evaluated the efficacy of acceptance and commitment therapy on impulsivity and suicidality among bipolar clients.MethodsIn a randomized controlled trial, 30 eligible clients with bipolar disorders were given Acceptance and Commitment Therapy, and 30 eligible clients for the control group were chosen randomly at a 1:1 ratio using Research Randomizer version 4.0. Clients completed the Acceptance and Action Questionnaire II, the Short Arabic Version of the Impulsivity Behavior Scale, and the Arabic Version of the Beck Scale for Suicide Ideation.ResultsIt can be observed that there was a statistically significant decrement in the mean scores of psychological inflexibility among the study group between baseline value (T0), posttest measurement (T1), and post-two-month follow-up (T2), from 32.91 SD (6.03) to 23.06 SD (6.22) post and 26.83 SD (3.49) post-two months, with an effect size of 0.846 (P < 0.001), compared to the control group, which revealed an increase in the mean score. The overall impulsivity among the study group between T0, T1, and T2 was 61.27 SD (4.57) to 46.83 SD (4.47) post- and 43.0 SD (5.30) post-two months, with an effect size of 0.906 (P < 0.001). Compared to the control group, which revealed a relative increase in the mean impulsivity score at the post- and post-two-month intervals, the Arabic Versions of the Beck Scale for Suicide Ideation Scale mean score before the intervention was 16.33 SD (6.08), then the post was 7.23 SD (4.72), and the post-two-month mean was 10.13 SD (5.49) with an effect size of 0.878 (P < 0.001) among the study group. On the other hand, mean scores of “suicide ideation” among clients in the control group increased posttest and nearly returned to the same value after two months.ConclusionFor bipolar clients suffering from suicidal thoughts and impulsive behaviors, acceptance and commitment therapy, an emerging third-wave behavior therapy, is an effective intervention.Trial registrationThe study was registered retrospectively with reference number NCT05693389 on 23/1/2023, available at: https://clinicaltrials.gov/ct2/show/NCT05693389.