Spencer Klein (born August 31, 1986) is an American musician and former child voice actor who provided the voice of Arnold Shortman in Hey Arnold!'s fourth season, most of the fifth season, and the theatrical film. He is often considered by fans to be the best/most memorable voice actor for Arnold, due to having the longest run with the character, with a total of 40 out of the original series' 103 half-hours (counting the movie as three).
As a drummer, he has collaborated with another former child voice actor-turned musician Shaun Fleming (best known by his stage name Diane Coffee).