Abstract: Suicide remains a critical concern within the United States, particularly among U.S. veterans. Anger is a known correlate of suicidal ideation (SI) but little is understood about their moment-to-moment relationship. This short communication uses ecological momentary assessment (EMA) data collected over a 28-day period to investigate the temporal association between anger and SI in 40 veterans diagnosed with nonsuicidal self-injury (NSSI) disorder. Using a multilevel cross-lagged design, we found that angry/hostile affect predicted subsequent SI; however, SI did not predict subsequent angry/hostile affect. These findings highlight anger as a potential trigger for suicidal thoughts and underscore the importance of addressing anger-related problems, especially among individuals at increased risk of suicide.