This study examined how the revealing of underlying vulnerable emotion relates to session and final outcome in the context of emotion‐focused therapy for couples. Segments of videotaped therapy sessions were rated on a measure of underlying vulnerable emotional expression for twenty‐five couples. Results indicated that partners rated sessions in which underlying vulnerable emotion was expressed significantly more positively than control sessions on a measure of session outcome. Moreover, from pre to post, couples who were found to have expressed underlying vulnerable emotion at least once improved significantly more on a measure of trust, and marginally significantly more on a measure of unfinished business, than couples who were not found to have expressed underlying vulnerable emotion. Recommendations for treatment are provided in light of the findings. Practitioner points It is recommended that couple therapists help partners to access and express underlying vulnerable emotion, because this appears to be associated with better session and final outcomes. When an underlying vulnerable emotion begins to emerge, it is recommended that the therapist maintain the focus on this emotion and help to facilitate its full expression.