Complementarity and symmetry are two terms that can be used to explain people’s characteristics in a relationship and the patterned ways people tend to interact. Complementary relationships comprise two or more people who tend to have different characteristics that together make a “whole.” Their characteristics balance each other out. One may be more extraverted and one more introverted. In a symmetrical relationship two people are similar in their styles. Having similarities can have advantages, but it can also lead to competitiveness. While these terms are most often used to classify romantic partnerships, they can also be seen in a variety of person-to-person relationships, such as family dyads and counseling relationships. This entry provides an overview of complementary and symmetrical relationships, highlighting findings on both the ...