Moses Hallett (July 16, 1834 – April 25, 1913) was a United States federal judge.
Born in Galena, Illinois, Hallett read law to enter the Bar in 1858. He was in private practice in Chicago, Illinois from 1859 to 1860. He was a gold miner in Colorado in 1860, returning to private practice in Denver, Colorado from 1861 to 1865. He was a member of the Colorado Territorial Council from 1863 to 1866. He was in private practice in Denver, Colorado in 1866. He was the chief U.S. Territorial Judge for the District Court for the Territory of Colorado from 1866 to 1877.
On January 9, 1877, following the admission of Colorado as a state, Hallett was nominated by President Ulysses Grant to a seat on the newly established United States District Court for the District of Colorado, created by 19 Stat. 61. He was confirmed by the United States Senate on January 12, 1877, receiving his commission the same day. Hallett served until April 7, 1906, when he retired.
Hallett was also a professor of Constitutional Law and Federal Jurisprudence at the University of Colorado at Boulder beginning in 1892. Following his retirement from the court, he was a real estate speculator in Denver, Colorado from 1906 to 1913. He was Dean emeritus at the University of Colorado at Boulder School of Law in 1913. He died that same year in Denver, Colorado and was buried in Denver's Fairmount Cemetery.