Although interpersonal communication is a defining feature of committed relationships, the quality of couple communication has not proven to be a straightforward cause of relationship quality. At the same time, emerging models argue that external circumstances likely combine with communication to generate changes in relationship quality. We integrate these 2 ideas by proposing that communication does exert effects on changes in relationship quality, but primarily when couples encounter challenging situations that require an adaptive response. In the present study we examine residential moves to different neighborhoods as one such adaptive challenge. We conducted a longitudinal study of 414 newlywed couples to examine whether observed communication moderates the effect of moving to higher- or lower-income neighborhoods on changes in relationship quality. Results indicate that communication exerts no main effects on relationship quality. Consistent with the proposed model, however, wives who displayed less positive, less effective, and more negative behaviors experienced greater decreases in relationship quality, but only when couples moved to substantially higher-income neighborhoods. Because communication may not affect relationship quality until couples encounter qualitatively new demands, strengthening relationships may pivot less on improving communication skills and more on ensuring that couples’ circumstances do not overwhelm the skills that they already possess.