| Frank Gordon Theis | |
| Office: | Senior Judge of the United States District Court for the District of Kansas |
| Term Start: | July 31, 1981 |
| Term End: | January 17, 1998 |
| Office1: | Chief Judge of the United States District Court for the District of Kansas |
| Term Start1: | 1977 |
| Term End1: | 1981 |
| Predecessor1: | Wesley E. Brown |
| Successor1: | Earl Eugene O'Connor |
| Office2: | Judge of the United States District Court for the District of Kansas |
| Term Start2: | March 4, 1967 |
| Term End2: | July 31, 1981 |
| Appointer2: | Lyndon B. Johnson |
| Predecessor2: | Seat established by 80 Stat. 75 |
| Successor2: | Sam A. Crow |
| Birth Name: | Frank Gordon Theis |
| Birth Date: | 26 June 1911 |
| Birth Place: | Yale, Kansas |
| Education: | University of Kansas (B.A.) University of Michigan Law School (J.D.) |
Frank Gordon Theis (June 26, 1911 – January 17, 1998) was a United States district judge of the United States District Court for the District of Kansas.
Born in Yale, Kansas, Theis received a Bachelor of Arts degree from the University of Kansas in 1933 and a Juris Doctor from the University of Michigan Law School in 1936. He was in private practice in Arkansas City, Kansas from 1936 to 1937, 1939 to 1950, and 1952 to 1967. He was an attorney for the Kansas Tax Commission from 1937 to 1939. He was deputy county attorney of Cowley County, Kansas from 1942 to 1946. He was chief counsel of the Office of Price Stabilization for Kansas from 1950 to 1952. He was city attorney of Arkansas City from 1955 to 1959.
Theis was an unsuccessful Democratic candidate for the Kansas 1960 United States Senate elections.
Theis was nominated by President Lyndon B. Johnson on January 16, 1967, to the United States District Court for the District of Kansas, to a new seat created by 80 Stat. 75. He was confirmed by the United States Senate on March 2, 1967, and received his commission on March 4, 1967. He served as Chief Judge from 1977 to 1981. He assumed senior status on July 31, 1981. Theis served in that capacity until his death on January 17, 1998.