Individuals with first-episode psychosis (FEP) are at increased risk for suicide, though few studies have examined the extent to which emotion regulation abnormalities contribute to this risk. The current study sought to address this gap by examining which stages of emotion regulation (ie, identification, selection, implementation) are related to suicidal ideation among individuals with FEP. Forty-one participants completed 28 days of ecological momentary assessment to assess suicidal ideation, negative affect, and emotion regulation in real-time. Results indicated that all 3 stages of emotion regulation were related to suicidal ideation in FEP. Specifically, within-person emotion regulation interacted with between-person negative affect to predict concurrent suicidal ideation (identification stage). Additionally, decreased use of adaptive strategies and increased use of maladaptive strategies were associated with more severe suicidal ideation (selection stage). Finally, decreased emotion regulation effectiveness was associated with more severe suicidal ideation (implementation stage). These findings suggest that emotion regulation difficulties might contribute to the high rates of suicide risk among individuals with FEP. Additional research is needed to determine whether these emotion regulation difficulties are unique to FEP or if they also appear in other high-risk groups.