Relationships, particularly those between men and women, are a central theme in The Da Vinci Code. The novel's central quest for the Holy Grail is ultimately unveiled as a search for the remains of the woman Jesus loved, who carried his child.

The concept of relationships between men and women is explicitly portrayed as a path to the divine. This notion is symbolized through the Hieros Gamos ceremony and the design of the cryptex. Additionally, this theme is evident in Sophie Neveu's strong connection with her grandfather, her reconciliation with her estranged grandmother by the novel's end, and the developing bond between Sophie and Robert Langdon.

The significance of human relationships is highlighted by the outcomes of those who ignore them. Silas ends up committing murder and experiencing heartbreak as his mission fails. Leigh Teabing resorts to murder and manipulation, only to see those he underestimated succeed in achieving his deepest desire. Hope for characters like Bishop Aringarosa is shown through his choice to donate his wealth to the families of the deceased as a form of partial atonement.

Notable quotations:
"The ability of the woman to produce life from her womb made her sacred. A god. Intercourse was the revered union of the two halves of the human spirit—male and female—through which the male could find spiritual wholeness and communion with God" (Chapter 74).

"'The legend of the Holy Grail is a legend about Royal Blood. When the Grail legend speaks of "the chalice that held the blood of Christ" … it speaks, in fact, of Mary Magdalene—the female womb that carried Jesus' royal bloodline'" (Chapter 58). Teabing's explanation of the Grail underscores that 2000 years of history and deceit have revolved around male-female relationships.