ObjectivesOncology patients are one of the groups with high suicide risk and it is emphasized that oncology nurses' suicide risk management knowledge and skills are insufficient. Several studies have underlined the need to create training programs specifically for oncology nurses to increase their level of awareness, knowledge, skill, and efficacy in recognizing and managing suicide risk. A valid and reliable scale is required to assess the efficacy of suicide risk management for oncology nurses. This study aimed to develop the Efficacy Perception Scale for Suicide Risk Management for Oncology Nurses and evaluate its psychometric properties. MethodsThis methodological study was conducted in two stages. In the first stage, the authors conducted a literature review and qualitative study and examined other efficacy scales to generate items. In the second stage, the validity and reliability of the 26 items were determined. The scale content was validated based on feedback from 10 experts. Exploratory analysis of the scale was conducted with the data of 234 oncology nurses. Internal consistency and 2-week test-retest stability measured reliability. ResultsThe scale's items met the required level of content validity (content validity rate = 0,62), were found to be understandable by 15 nurse (face validity), and all 26 items were retained in the item pool. The exploratory factor analysis extracted a unifactorial solution for the scale. The value of Cronbach's alpha for the scale was 0.96, and the inter-class reliability coefficient was 0.92. ConclusionThe scale is a valid and reliable scale that might be used to assess the efficacy perception of oncology nurses for suicide risk management. Implications for Nursing PracticeThe assessment of oncology nurses' perceptions of efficacy in suicide risk management may enable the identification of training needs and the development of the content of suicide prevention trainings in parallel with the needs of nurses.