Mayo, a 6-3, 190-pounder, will arrive on campus this summer and have four years of eligibility with the Golden Eagles.
"We are really excited to add Todd to our 2011 class," Williams said. "He is the perfect complement to what we lost and what we have returning. He has been around the game his entire life and we are grateful that he believed our culture was what was best for his future.
"We have really enjoyed building a relationship with Todd and his family and look forward to having him here early this summer, in preparation for his freshman year," Williams added.
The Huntington, W.V., native helped Notre Dame Prep to the National Prep Championship game in 2010-11, averaging 22.0 points and 6.0 assists per game. In the three outings at the national tournament, Mayo averaged 28.3 points per contest to lead all players. The team posted an overall record of 33-4 and Mayo is ranked among the top-10 players in the region.
Mayo played at Germantown High School in Tennessee in 2009-10 and at rival Houston High School as a junior in 2008-09.
As a sophomore in 2007-08, Mayo averaged 22.6 points per game and shot 47.0 percent from the floor at South Point High School in Ohio. He led the Pointers to an undefeated 20-0 overall record in the regular season and the program's first Ohio Valley Conference title since 1990.
The brother of current Memphis Grizzlies guard O.J. Mayo, he played football as a freshman in high school before focusing on basketball.
Mayo joins forward Juan Anderson (Castro Valley, Calif./Castro Valley HS) and point guard Derrick Wilson (Anchorage, Alaska/The Hotchkiss School) in Marquette's 2011 recruiting class.