The Lancaster County jury deliberated one hour Thursday before acquitting 33-year-old Matthew Deppen of all charges.
Deppen was charged with sexual abuse of children after taping the girls at his Lancaster-area home.
Deppen maintained he had planned to play a prank on the girls by surprising them while wearing a mask, but didn't because they were changing. He said he didn't know the tape contained anything improper.
Police arrested Deppen in January after his estranged wife turned the tape over to police. He was suspended from his job in the Manheim Central School District following his arrest.
Prosecutors declined comment on the ruling.
Information from: Intelligencer Journal/Lancaster New Era , http://lancasteronline.com