A longitudinal study with romantic couples was conducted to examine the importance of equity relative to other social exchange variables (i.e., rewards, investments, and alternatives) in predicting relationship satisfaction, commitment, and stability. Underbenefiting inequity (but not overbenefiting inequity) was associated with a lower level of satisfaction and commitment and a greater likelihood of breakup. However, little evidence was found that equity at one time predicted change in satisfaction and commitment. Slightly more evidence was found for a reverse causal direction: Satisfaction and commitment contributed to a decrease in underbenefiting inequity, although these results were not consistent across time. Women's commitment was the strongest predictor of relationship stability. In addition, women's underbenefiting inequity and alternatives and men's alternatives were associated with breakups in some of the analyses, and women's rewards and satisfaction and men's satisfaction were associated with relationship stability in some of the analyses. Because of the multiple waves and the extended length of the longitudinal study, the findings make a unique contribution to the literature on equity and exchange.