Relationship self-regulation (SR) is how much partners work at their couple relationship, and it has been hypothesized to predict relationship satisfaction. To test this hypothesis, the authors assessed 191 newlywed couples on SR and relationship satisfaction annually for 5 years. They conducted a multilevel analysis predicting satisfaction with SR as a time-varying covariate. The intercept and slope of relationship satisfaction varied across participants, and the slope showed an average slight decline for both men and women. There was mixed support for the primary hypothesis. SR cross-sectionally and prospectively predicted the intercept, but it did not predict the slope, of relationship satisfaction.