This study examined the ability of the therapeutic alliance to predict treatment progress on individual‐ and relationship‐level variables from the early to middle phase of couple treatment. Although alliance did not predict progress in individual functioning, it accounted for 5–22% of the variance in improvement in marital distress. Women’s mid‐treatment alliance uniquely predicted improvement in marital distress, over and above early treatment alliance. When men’s alliances with the therapist were stronger than their partners’ at session 8, couples showed more improvement in marital distress. Treatment response was also positively associated with women’s ratings of their partners’ alliance. Results confirm that the therapeutic alliance in conjoint treatment is composed of distinct client subsystems that are useful predictors of treatment progress.