| Rainbow Fraternity | |
|---|---|
| W.W.W. | |
 Rainbow Fraternity badge for Vanderbilt University chapter, circa 1898 | |
| Founded | 1849 University of Mississippi |
| Type | Social |
| Affiliation | Independent |
| Status | Merged |
| Merge Date | 1886 |
| Successor | Delta Tau Delta |
| Scope | Regional (Southern United States) |
| Colors | Red Orange Yellow Green Cyan Blue Violet |
| Symbol | Rainbow |
| Patron Greek divinity | Iris |
| Publication | The Rainbow |
| Chapters | 13 |
| Other names | Mystic Sons of Iris and W.W.W. Society |
| Headquarters | United States |
Rainbow Fraternity, also known as Mystic Sons of Iris and W.W.W. Society, was a United States–based fraternity founded in the antebellum south that merged with Delta Tau Delta in 1886.