Relationship quality is the most frequently assessed construct in the intimate relationships literature. Dozens of assessment instruments exist, but the vast majority conceptualize relationship quality in terms of satisfaction (or a similar construct), which focuses on the hedonic (pleasure or happiness) dimension of the relationship. Some scholars question whether the richness and depth of adult intimate relationships can be captured by satisfaction ratings and suggest focusing on a complementary eudaimonic (human flourishing) dimension of the relationship. This study evaluates the development of the Relationship Flourishing Scale, a 12-item measure of eudaimonic relationship quality that assesses meaning, personal growth, relational giving, and goal sharing. The study supports the construct validity of the Relationship Flourishing Scale, including its content, concurrent, convergent, discriminant, and incremental validity. Its incremental validity and independence suggest that it provides information about deeper and richer aspects of relationship quality than do current hedonic relationship quality measures. (PsycINFO Database Record