Bowen family systems theory provides an account of how the family of origin promotes intimate connections with others. The study tests the mediating role of emotional expressivity in the relationship between differentiation of self and co-dependency assessed in married couples. We used a common fate model to study the relationship among these variables in a sample of 176 Turkish heterosexual married couples (N = 352). Results showed that lower differentiation of self predicted greater co-dependency among couples. Emotional expressivity mediated this relationship between the differentiation of self and co-dependency. Implications of the findings were discussed.