Like his brothers, he was originally voiced by Ross Bagdasarian, Sr. In the animated series and film, he was voiced by Ross Bagdasarian, Jr. Matthew Gray Gubler voiced Simon in the live-action/animated film series.
Like his brothers, he was originally voiced by Ross Bagdasarian, Sr. In the animated series and film, his voice was provided by Janice Karman, Ross Bagdasarian Jr. 's wife and the voice of all three Chipettes. Jesse McCartney voiced Theodore in the live-action/animated film series.