| Nelson McVicar | |
| Office: | Senior Judge of the United States District Court for the Western District of Pennsylvania |
| Term Start: | February 1, 1951 |
| Term End: | December 20, 1960 |
| Office1: | Chief Judge of the United States District Court for the Western District of Pennsylvania |
| Term Start1: | 1949 |
| Term End1: | 1951 |
| Predecessor1: | Robert Murray Gibson |
| Successor1: | Wallace Samuel Gourley |
| Office2: | Judge of the United States District Court for the Western District of Pennsylvania |
| Term Start2: | September 14, 1928 |
| Term End2: | February 1, 1951 |
| Appointer2: | Calvin Coolidge |
| Predecessor2: | W. H. Seward Thomson |
| Successor2: | William Alvah Stewart |
| Birth Name: | Nelson McVicar |
| Birth Date: | 25 January 1871 |
| Birth Place: | Chatham, Ontario, Canada |
| Death Place: | Tarentum, Pennsylvania |
| Education: | University of Michigan Law School read law |
Nelson McVicar (January 25, 1871 – December 20, 1960) was a United States district judge of the United States District Court for the Western District of Pennsylvania.
Born in Chatham (now Chatham-Kent), Ontario, Canada, McVicar attended the University of Michigan Law School and read law to enter the bar in 1896. From 1896 to 1925, he was in private practice in Pittsburgh, Pennsylvania, and was a borough solicitor for Tarentum Borough, Pennsylvania. He was a member of the Pennsylvania House of Representatives from 1914 to 1924, and was a Judge of the Court of Common Pleas for Allegheny County, Pennsylvania from 1925 to 1928.
McVicar received a recess appointment from President Calvin Coolidge on September 14, 1928, to a seat on the United States District Court for the Western District of Pennsylvania vacated by Judge W. H. Seward Thomson. He was nominated to the same position by President Coolidge on December 6, 1928. He was confirmed by the United States Senate on December 17, 1928, and received his commission the same day. He served as Chief Judge from 1949 to 1951. He assumed senior status on February 1, 1951. His service terminated on December 20, 1960, due to his death in Tarentum.