| Robert E. Lewis | |
| Office: | Senior Judge of the United States Court of Appeals for the Tenth Circuit |
| Term Start: | May 31, 1940 |
| Term End: | July 31, 1941 |
| Office1: | Judge of the United States Court of Appeals for the Tenth Circuit |
| Term Start1: | March 28, 1929 |
| Term End1: | May 31, 1940 |
| Appointer1: | operation of law |
| Predecessor1: | Seat established by 45 Stat. 1346 |
| Successor1: | Alfred P. Murrah |
| Office2: | Judge of the United States Court of Appeals for the Eighth Circuit |
| Term Start2: | November 15, 1921 |
| Term End2: | March 28, 1929 |
| Appointer2: | Warren G. Harding |
| Predecessor2: | William Cather Hook |
| Successor2: | Seat abolished |
| Office3: | Judge of the United States District Court for the District of Colorado |
| Term Start3: | April 10, 1906 |
| Term End3: | December 1, 1921 |
| Appointer3: | Theodore Roosevelt |
| Predecessor3: | Moses Hallett |
| Successor3: | John Foster Symes |
| Birth Name: | Robert E. Lewis |
| Birth Date: | 3 April 1857 |
| Birth Place: | Cass County, Missouri |
| Death Place: | Denver, Colorado |
| Party: | Republican |
| Education: | Westminster College read law |
Robert E. Lewis (April 3, 1857 – July 31, 1941) was a United States circuit judge of the United States Court of Appeals for the Eighth Circuit and the United States Court of Appeals for the Tenth Circuit and previously was a United States district judge of the United States District Court for the District of Colorado.
Born in Cass County, Missouri, Lewis studied at Westminster College in Fulton, Missouri. Afterward, he read law to enter the bar in 1880. Lewis was then in private practice in Clinton, Missouri from 1880 to 1897, and as worked as a prosecuting attorney of Henry County, Missouri from 1883 to 1887. He was also a Republican candidate for Governor of Missouri in 1896 and a Judge of the 4th Judicial District of Colorado from 1903 to 1906.
Lewis was nominated by President Theodore Roosevelt on April 9, 1906, to a seat on the United States District Court for the District of Colorado vacated by Judge Moses Hallett. He was confirmed by the United States Senate on April 10, 1906, and received his commission the same day. His service terminated on December 1, 1921, due to his elevation to the Eighth Circuit.
Lewis was nominated by President Warren G. Harding on November 3, 1921, to a seat on the United States Court of Appeals for the Eighth Circuit vacated by Judge William Cather Hook. He was confirmed by the Senate on November 15, 1921, and received his commission the same day. Lewis was reassigned by operation of law to the United States Court of Appeals for the Tenth Circuit on March 28, 1929, to a new seat authorized by 45 Stat. 1346. He was a member of the Conference of Senior Circuit Judges (now the Judicial Conference of the United States) from 1929 to 1940. He assumed senior status on May 31, 1940. He was the last appeals court judge who continued to serve in active service appointed by President Harding. His service ended on July 31, 1941, with his death.