Retrospective and experimental data demonstrate the importance of emotion regulation (ER) in the maintenance of binge episodes in binge eating disorder (BED). The current study tested whether mood and ER prospectively influence binge episodes in individuals with BED via ecological momentary assessment (EMA). Individuals with BED (n = 79) completed two weeks of EMA. Each sampling point consisted of a series of questions pertaining to participants' mood, ER, and eating behaviour. Successful application of adaptive ER strategies predicted subsequent abstinence, while rumination predicted subsequent binge episodes. However, neither successful application of adaptive ER, nor maladaptive ER, moderated the association between negative mood and probability of binge episodes. This naturalistic study emphasizes the importance of promoting the successful application of adaptive ER skills and cessation of rumination in treatment interventions designed to decrease the occurrence of binge episodes in BED.