Background: The self-report measures used in evaluations of the Applied Suicide Intervention Skills Training (ASIST) program have tended not to detect an improvement in a broad range of suicide counseling skills from pre- to posttraining or among trainees with better skills at pretraining. Aims: The purpose of this study was to develop and validate the Suicide Counseling Skills Inventory (SCSI), which included ten brief counselor–client scenarios and three counselor responses to each scenario. Method: Data were collected from several samples to develop and evaluate the SCSI. Trainee scores were subtracted from criterion expert scores to create discrepancy scores. Results: The SCSI detected an improvement in skills from pre- to posttraining across samples, including among trainees with better skills at pretraining. Internal consistency and test–retest reliability were good. Limitations: The results may not generalize across different training models. Conclusion: Trainee scores were more like expert scores at posttraining. The SCSI may be useful in evaluating suicide counseling competency.