Is there a connection between the exchange of vows and the fighting and suffering of couples that are unique to the institution of marriage? This essay introduces the concept of Shadow Vows, the unacknowledged assumptions, agreements, and obligations each partner brings to the relationship, which the authors believe are often responsible for longstanding marital discord and strife. The authors ground the existence of shadow vows in Jung's quaternity, alchemy, typology, archetypal theory, and depth approaches to couple therapy. The essay concludes with a list of themes indicative of shadow vow enactments in clinical work with couples.