In relationship astrology, a House Overlay occurs when the planets or other chart factors from one person’s natal chart are placed within the houses of another person’s chart for comparison. Astrologers may use house overlays to explore which areas of life are symbolically emphasized through the interaction between two people. For example, one person’s planet falling within another person’s particular house may be interpreted as highlighting themes associated with that house in the relationship. House overlays are commonly used alongside synastry aspects, planetary contacts, and other comparative techniques. They offer a symbolic way to examine interpersonal dynamics and do not by themselves determine compatibility, relationship quality, or outcome.