I am not aware of any restrictions. However, like any website, I would expect that anyone under age 13 is only playing with their parents permission and active monitoring. I know that there have been players as young as 10 (and as old as 70something). The fun thing about WIS is that the main criteria is to love sports and that spans all ages and social orientation. There have been users (men and women) ranging from Junior High School/High School students, to accountants, CEOs, Billboard charting singers/musicians, best-selling authors, truck drivers, doctors/dentists, lawyers, television screenwriters, military members, ESPN personalities, Elias Sports Bureau statistictions, college basketball coaches, teachers, professional sports athletes, professors, pastors, mechanics, retirees, and just about any other profession/career field you can think of.