This is a longitudinal couples therapy process study using coded data from eleven couples to identify which therapist behaviors (warmth, listener responsiveness, communication, dominance) influenced positive couples exchanges (warmth and listener responsiveness) over time in Emotionally Focused Couples Therapy (EFT). A mixed effects model was used to examine within- and between-individual variability. Men and women were modeled separately. A series of two-level multilevel models of change were examined, where Time is Level 1 and Individual is Level 2. Results indicated no significant relationship between variables of therapist warmth, listener responsiveness, communication, and dominance with couple listener responsiveness. Where client warmth was an outcome variable, the only significant relationship was between therapist warmth toward husband and husband warmth toward wife. Findings demonstrated that 62.9% of the variance in husband warmth toward wife was accounted for by therapist warmth to husband across time in therapy. Specifically, therapist warmth toward husband was significantly and positively related to husband warmth toward wife over time in therapy. Clinical implications and directions for future research are discussed.