Sigma Alpha Iota is an international honorary music fraternity. It was founded on June 12, 1903 at the School of Music of the University of Michigan as an honorary music sorority.
Collegiate chapters.
In the following list, active chapters are indicated in bold and inactive chapters and institutions are in "italics". 
Alumnae chapters.
In the following list of alumnae chapters, active chapters are indicated in bold and inactive chapters are in "italics".