This study examined whether therapist gender, professional discipline, experience conducting couple therapy, and average second-session alliance score would account for the variance in outcomes attributed to the therapist. The authors investigated therapist variability in couple therapy with 158 couples randomly assigned to and treated by 18 therapists in a naturalistic setting. Consistent with previous studies in individual therapy, in this study therapists accounted for 8.0% of the variance in client outcomes and 10% of the variance in client alliance scores. Therapist average alliance score and experience conducting couple therapy were salient predictors of client outcomes attributed to therapist. In contrast, therapist gender and discipline did not significantly account for the variance in client outcomes attributed to therapists. Tests of incremental validity demonstrated that therapist average alliance score and therapist experience uniquely accounted for the variance in outcomes attributed to the therapist. Emphasis on improving therapist alliance quality and specificity of therapist experience in couple therapy are discussed.