Charles Prentiss Orr (February 22, 1858 – May 16, 1922) was a United States federal judge.
Born in Allegheny, Pennsylvania, Orr received an A.B. from Hamilton College in 1879 and read law to enter the bar in 1881. He was in private practice in Pittsburgh, Pennsylvania from 1886 to 1909.
On March 25, 1909, Orr was nominated by President William H. Taft to a new seat on the United States District Court for the Western District of Pennsylvania created by 35 Stat. 656. He was confirmed by the United States Senate on April 8, 1909, and received his commission the same day. Orr served in that capacity until his death, in 1922.