Rabe Ferguson Marsh, Jr. (April 26, 1905 – April 19, 1993) was a United States federal judge.
Born in Greensburg, Pennsylvania, Marsh received an A.B. from Lafayette College in 1927 and an LL.B. from the University of Pittsburgh School of Law in 1930. He was in private practice in Greensburg from 1930 to 1950. He was an assistant district attorney of Westmoreland County, Pennsylvania from 1942 to 1950.
On March 27, 1950, Marsh was nominated by President Harry S. Truman to a seat on the United States District Court for the Western District of Pennsylvania vacated by Robert M. Gibson. Marsh was confirmed by the United States Senate on June 2, 1950, and received his commission on June 8, 1950. He served as chief judge from 1969 to 1975, and assumed senior status on January 31, 1977. Marsh served in that capacity until his death, in 1993, in Greensburg, Pennsylvania.