Childhood abuse and/or neglect adversely influences development of neurocognitive systems that regulate affect and behavior. Poor inhibitory control over emotional reactions is thus one potential pathway from maltreatment to suicide. Adult psychiatric inpatients completed the Childhood Trauma Questionnaire and an emotional stop-signal task indexing negative emotional action termination (NEAT): the ability to inhibit ongoing motor reactions to aversive stimuli triggered by negative affect. Clinical interviews assessed suicidal thoughts and behaviors during hospitalization (n = 131) and at follow-up assessments 6 months later (n = 87). Our primary aim was to examine whether maltreatment history and NEAT explain overlapping variance in suicidal behaviors (1) retrospectively and (2) 6 months following hospital discharge. Contrary to prediction, childhood maltreatment was unrelated to history of suicidal behaviors. However, NEAT was consistently associated with prior suicidal acts, even controlling for suicidal ideation and demographic covariates. NEAT similarly contributed to the prediction of post-discharge suicidal behaviors, whereas we found no effect of maltreatment history. The present study suggests that NEAT captures suicide risk independently of childhood maltreatment. Results implicated NEAT impairment specifically, rather than broader response inhibition deficits (e.g., to positive stimuli), in past and future suicidal behaviors. These findings provide preliminary support for NEAT as a behavioral vulnerability marker for suicide, with implications for understanding links between maltreatment history and suicidal acts.