This article reviews the usefulness of the systemic concept of triangulation as a bridge between systemic thinking and practice and attachment theory. Traditionally attachment theory has theorized and researched with dyads, parent-child and adult romantic partners, whereas systemic theory has worked therapeutically with the triangle as the basic human relationship; that is, when any two people interact, their interactions are influenced by their respective relationships with the same third person. Here it is argued, for example, that a child’s attachment representations are shaped not only by the relationship with each parent but with the relationship between them. Thus, the process of triangulation in intimate relationships is seen in this article to link attachment theory with systemic thinking, as systemic theory needs a theory of love and attachment theory needs to consider how intimate relationships are nested and interconnected in an attachment network.