The therapeutic alliance in individual and group psychotherapy is associated with treatment outcomes for a variety of disorders. However, debate persists about the centrality of the alliance in determining positive outcomes. We examined the alliance–outcome relationship across 20 sessions of emotionally focused group therapy (EFGT) for binge-eating disorder (BED). We hypothesized that (1) previous session alliance increase will predict lower subsequent session binge eating level while controlling for previous session binge eating level; and (2) previous session binge eating decline will predict higher subsequent session alliance level while controlling previous session alliance level. Participants were 118 individuals with BED who received 20 sessions of EFGT in 8 groups. Levels of binge eating and therapeutic alliance to the therapist were measured weekly. Linear growth in alliance during group therapy was associated with reduced binge eating at 6 months’ posttreatment. We also found that the group’s and the individual’s alliance scores and binge-eating episodes were significantly associated across treatment, suggesting a mutual influence of the group’s and individual’s experience of the alliance with the therapist. Regarding the first hypothesis, previous session alliance increase was significantly associated with lower subsequent session binge eating. Regarding the second hypothesis, previous session binge-eating decline was not significantly related to higher subsequent session alliance. The findings provide evidence in a group therapy context for a model in which alliance change influences subsequent symptom levels, but not the other way around.