Vonleh is from Haverhill in Massachusetts and plays for New Hampton Prep School. He was originally in the Class of 2014 before reclassifying.
Vonleh committed after visiting IU this weekend. That included attending the Hoosiers' season-opening win over Bryant Friday night where Assembly Hall fans chanted his name.
Among the schools IU beat out were North Carolina, Kansas, Florida, UCLA and Arizona.
Vonleh is the sixth player in the Hoosiers' class. The others are small forward Troy Williams (ranked No. 37), shooting guard Stanford Robinson (No. 50), small forward Devin Davis (No. 120), small forward Collin Hartman (not ranked) and center Luke Fischer (No. 115).
Wednesday is the first day of the official fall signing period.