In the present study we explored the relationship between personality characteristics and relationship satisfaction in couples. Using a sample of 14,807 couples from the RELATE dataset, a model was tested examining the direct and indirect (via self-esteem) associations between personality traits (i.e., shyness) and relationship satisfaction. Furthermore, the model assessed shyness, self-esteem, and relationship satisfaction for both partners in the relationship. The results indicated that higher levels of shyness were associated with lower self-esteem in individuals, as well as lower relationship satisfaction. Implications of results and the use of partner ratings of personality indicators are discussed.