Researchers at the University of Virginia analysed new data from the Relationship Development Study, an ongoing national study based at the University of Denver.
Between 2007 and 2008, more than 1,000 Americans who were unmarried but in a relationship, and between the ages of 18 and 34, were recruited into the study.
Over the course of the next five years and 11 waves of data collection, 418 of those individuals got married.
The study found that having more guests at one's wedding, the biggest ritual in many relationships, is associated with higher marital quality, even after controlling for income and education, which may be proxies for how much the wedding might have cost.
Among couples who had weddings, the sample was divided into those who had weddings with 50 or fewer attendees, 51 to 149 attendees, or 150 or more attendees.
Among each grouping, 31 per cent, 37 per cent, and 47 per cent, respectively, reported high marital quality, researchers said.
"In what might be called the 'My Big Fat Greek Wedding' factor, this study finds that couples who have larger wedding parties are more likely to report high-quality marriages," said W Bradford Wilcox, director of the National Marriage Project and a professor of sociology at UVa.
"One possibility here is that couples with larger networks of friends and family may have more help, and encouragement, in navigating the challenges of married life.
"Note, however, this finding is not about spending lots of money on a wedding party. It's about having a good number of friends and family in your corner," said Wilcox.