Insomnia-related sleep problems are common in borderline personality disorder (BPD) and exacerbate the core of BPD, emotion dysregulation. Insomnia is elicited and maintained through behaviors that disrupt both the homeostatic and circadian sleep systems. However, it is unclear which homeostatic or circadian insomnia behaviors characterize BPD and exacerbate emotion dysregulation, thus warranting clinical attention in this population. This study therefore investigated whether homeostatic (i.e., abnormalities in time in bed and sleep efficiency [SE]) and circadian (i.e., abnormalities in risetime variability and chronotypes) behaviors characterize and exacerbate emotion dysregulation in BPD group relative to healthy control (HC) and generalized anxiety disorder (GAD) groups. Participants from the community who met criteria for BPD, GAD, or no psychological disorders (HCs) were recruited and completed measures of emotion dysregulation. They also completed measures of daily homeostatic and circadian insomnia behaviors for 14 days. Generalized estimating equations revealed that the GAD group exhibited lower SE than HCs, and there was a marginally significant effect wherein the BPD group exhibited delayed risetimes relative to the GAD group. Moreover, higher time in bed predicted elevated emotion dysregulation in HCs but lower emotion dysregulation in the GAD group. Higher SE predicted higher emotion dysregulation in BPD. These results suggest that the influence of insomnia behaviors on emotion dysregulation is heterogeneous. Idiographic assessments of the influence of insomnia behaviors on emotion dysregulation are advised. (PsycInfo Database Record (c) 2020 APA, all rights reserved).